DO NOT MERGE: Eliminate StackBox.

StackBox is too constraining. Adding size and position to TaskStacks
directly makes stack positioning and management more flexible and
prepares for ActivityView.

Change-Id: I33c6b4e1c23a5a8069fd507c160bcb34e4d287b2
diff --git a/cmds/am/src/com/android/commands/am/Am.java b/cmds/am/src/com/android/commands/am/Am.java
index 0344d26..f3432a0 100644
--- a/cmds/am/src/com/android/commands/am/Am.java
+++ b/cmds/am/src/com/android/commands/am/Am.java
@@ -19,7 +19,7 @@
 package com.android.commands.am;
 
 import android.app.ActivityManager;
-import android.app.ActivityManager.StackBoxInfo;
+import android.app.ActivityManager.StackInfo;
 import android.app.ActivityManagerNative;
 import android.app.IActivityController;
 import android.app.IActivityManager;
@@ -31,6 +31,7 @@
 import android.content.Intent;
 import android.content.pm.IPackageManager;
 import android.content.pm.ResolveInfo;
+import android.graphics.Rect;
 import android.net.Uri;
 import android.os.Binder;
 import android.os.Bundle;
@@ -106,11 +107,11 @@
                 "       am to-intent-uri [INTENT]\n" +
                 "       am switch-user <USER_ID>\n" +
                 "       am stop-user <USER_ID>\n" +
-                "       am stack create <TASK_ID> <RELATIVE_STACK_BOX_ID> <POSITION> <WEIGHT>\n" +
+                "       am stack create <TASK_ID>\n" +
                 "       am stack movetask <TASK_ID> <STACK_ID> [true|false]\n" +
-                "       am stack resize <STACK_ID> <WEIGHT>\n" +
-                "       am stack boxes\n" +
-                "       am stack box <STACK_BOX_ID>\n" +
+                "       am stack resize <STACK_ID> <LEFT,TOP,RIGHT,BOTTOM>\n" +
+                "       am stack list\n" +
+                "       am stack info <STACK_ID>\n" +
                 "\n" +
                 "am start: start an Activity.  Options are:\n" +
                 "    -D: enable debugging\n" +
@@ -204,24 +205,16 @@
                 "am stop-user: stop execution of USER_ID, not allowing it to run any\n" +
                 "  code until a later explicit switch to it.\n" +
                 "\n" +
-                "am stack create: create a new stack relative to an existing one.\n" +
-                "   <TASK_ID>: the task to populate the new stack with. Must exist.\n" +
-                "   <RELATIVE_STACK_BOX_ID>: existing stack box's id.\n" +
-                "   <POSITION>: 0: before <RELATIVE_STACK_BOX_ID>, per RTL/LTR configuration,\n" +
-                "               1: after <RELATIVE_STACK_BOX_ID>, per RTL/LTR configuration,\n" +
-                "               2: to left of <RELATIVE_STACK_BOX_ID>,\n" +
-                "               3: to right of <RELATIVE_STACK_BOX_ID>," +
-                "               4: above <RELATIVE_STACK_BOX_ID>, 5: below <RELATIVE_STACK_BOX_ID>\n" +
-                "   <WEIGHT>: float between 0.2 and 0.8 inclusive.\n" +
+                "am stack create: create a new stack containing <TASK_ID> which must exist\n" +
                 "\n" +
                 "am stack movetask: move <TASK_ID> from its current stack to the top (true) or" +
                 "   bottom (false) of <STACK_ID>.\n" +
                 "\n" +
-                "am stack resize: change <STACK_ID> relative size to new <WEIGHT>.\n" +
+                "am stack resize: change <STACK_ID> size and position to <LEFT,TOP,RIGHT,BOTTOM>.\n" +
                 "\n" +
-                "am stack boxes: list the hierarchy of stack boxes and their contents.\n" +
+                "am stack list: list all of the activity stacks and their sizes.\n" +
                 "\n" +
-                "am stack box: list the hierarchy of stack boxes rooted at <STACK_BOX_ID>.\n" +
+                "am stack info: display the information about activity stack <STACK_ID>.\n" +
                 "\n" +
                 "<INTENT> specifications include these flags and arguments:\n" +
                 "    [-a <ACTION>] [-d <DATA_URI>] [-t <MIME_TYPE>]\n" +
@@ -1551,11 +1544,11 @@
         } else if (op.equals("movetask")) {
             runStackMoveTask();
         } else if (op.equals("resize")) {
-            runStackBoxResize();
-        } else if (op.equals("boxes")) {
-            runStackBoxes();
-        } else if (op.equals("box")) {
-            runStackBoxInfo();
+            runStackResize();
+        } else if (op.equals("list")) {
+            runStackList();
+        } else if (op.equals("info")) {
+            runStackInfo();
         } else {
             showError("Error: unknown command '" + op + "'");
             return;
@@ -1565,15 +1558,9 @@
     private void runStackCreate() throws Exception {
         String taskIdStr = nextArgRequired();
         int taskId = Integer.valueOf(taskIdStr);
-        String relativeToStr = nextArgRequired();
-        int relativeTo = Integer.valueOf(relativeToStr);
-        String positionStr = nextArgRequired();
-        int position = Integer.valueOf(positionStr);
-        String weightStr = nextArgRequired();
-        float weight = Float.valueOf(weightStr);
 
         try {
-            int stackId = mAm.createStack(taskId, relativeTo, position, weight);
+            int stackId = mAm.createStack(taskId);
             System.out.println("createStack returned new stackId=" + stackId + "\n\n");
         } catch (RemoteException e) {
         }
@@ -1601,34 +1588,40 @@
         }
     }
 
-    private void runStackBoxResize() throws Exception {
-        String stackBoxIdStr = nextArgRequired();
-        int stackBoxId = Integer.valueOf(stackBoxIdStr);
-        String weightStr = nextArgRequired();
-        float weight = Float.valueOf(weightStr);
+    private void runStackResize() throws Exception {
+        String stackIdStr = nextArgRequired();
+        int stackId = Integer.valueOf(stackIdStr);
+        String leftStr = nextArgRequired();
+        int left = Integer.valueOf(leftStr);
+        String topStr = nextArgRequired();
+        int top = Integer.valueOf(topStr);
+        String rightStr = nextArgRequired();
+        int right = Integer.valueOf(rightStr);
+        String bottomStr = nextArgRequired();
+        int bottom = Integer.valueOf(bottomStr);
 
         try {
-            mAm.resizeStackBox(stackBoxId, weight);
+            mAm.resizeStack(stackId, new Rect(left, top, right, bottom));
         } catch (RemoteException e) {
         }
     }
 
-    private void runStackBoxes() throws Exception {
+    private void runStackList() throws Exception {
         try {
-            List<StackBoxInfo> stackBoxes = mAm.getStackBoxes();
-            for (StackBoxInfo info : stackBoxes) {
+            List<StackInfo> stacks = mAm.getAllStackInfos();
+            for (StackInfo info : stacks) {
                 System.out.println(info);
             }
         } catch (RemoteException e) {
         }
     }
 
-    private void runStackBoxInfo() throws Exception {
+    private void runStackInfo() throws Exception {
         try {
-            String stackBoxIdStr = nextArgRequired();
-            int stackBoxId = Integer.valueOf(stackBoxIdStr);
-            StackBoxInfo stackBoxInfo = mAm.getStackBoxInfo(stackBoxId); 
-            System.out.println(stackBoxInfo);
+            String stackIdStr = nextArgRequired();
+            int stackId = Integer.valueOf(stackIdStr);
+            StackInfo info = mAm.getStackInfo(stackId);
+            System.out.println(info);
         } catch (RemoteException e) {
         }
     }
diff --git a/core/java/android/app/ActivityManager.java b/core/java/android/app/ActivityManager.java
index 7ca3459..c877cd3 100644
--- a/core/java/android/app/ActivityManager.java
+++ b/core/java/android/app/ActivityManager.java
@@ -1289,106 +1289,15 @@
     }
 
     /**
-     * Information you can retrieve about the WindowManager StackBox hierarchy.
-     * @hide
-     */
-    public static class StackBoxInfo implements Parcelable {
-        public int stackBoxId;
-        public float weight;
-        public boolean vertical;
-        public Rect bounds;
-        public StackBoxInfo[] children;
-        public int stackId;
-        public StackInfo stack;
-
-        @Override
-        public int describeContents() {
-            return 0;
-        }
-
-        @Override
-        public void writeToParcel(Parcel dest, int flags) {
-            dest.writeInt(stackBoxId);
-            dest.writeFloat(weight);
-            dest.writeInt(vertical ? 1 : 0);
-            bounds.writeToParcel(dest, flags);
-            dest.writeInt(stackId);
-            if (children != null) {
-                children[0].writeToParcel(dest, flags);
-                children[1].writeToParcel(dest, flags);
-            } else {
-                stack.writeToParcel(dest, flags);
-            }
-        }
-
-        public void readFromParcel(Parcel source) {
-            stackBoxId = source.readInt();
-            weight = source.readFloat();
-            vertical = source.readInt() == 1;
-            bounds = Rect.CREATOR.createFromParcel(source);
-            stackId = source.readInt();
-            if (stackId == -1) {
-                children = new StackBoxInfo[2];
-                children[0] = StackBoxInfo.CREATOR.createFromParcel(source);
-                children[1] = StackBoxInfo.CREATOR.createFromParcel(source);
-            } else {
-                stack = StackInfo.CREATOR.createFromParcel(source);
-            }
-        }
-
-        public static final Creator<StackBoxInfo> CREATOR =
-                new Creator<ActivityManager.StackBoxInfo>() {
-
-            @Override
-            public StackBoxInfo createFromParcel(Parcel source) {
-                return new StackBoxInfo(source);
-            }
-
-            @Override
-            public StackBoxInfo[] newArray(int size) {
-                return new StackBoxInfo[size];
-            }
-        };
-
-        public StackBoxInfo() {
-        }
-
-        public StackBoxInfo(Parcel source) {
-            readFromParcel(source);
-        }
-
-        public String toString(String prefix) {
-            StringBuilder sb = new StringBuilder(256);
-            sb.append(prefix); sb.append("Box id=" + stackBoxId); sb.append(" weight=" + weight);
-            sb.append(" vertical=" + vertical); sb.append(" bounds=" + bounds.toShortString());
-            sb.append("\n");
-            if (children != null) {
-                sb.append(prefix); sb.append("First child=\n");
-                sb.append(children[0].toString(prefix + "  "));
-                sb.append(prefix); sb.append("Second child=\n");
-                sb.append(children[1].toString(prefix + "  "));
-            } else {
-                sb.append(prefix); sb.append("Stack=\n");
-                sb.append(stack.toString(prefix + "  "));
-            }
-            return sb.toString();
-        }
-
-        @Override
-        public String toString() {
-            return toString("");
-        }
-    }
-
-    /**
      * Information you can retrieve about an ActivityStack in the system.
      * @hide
      */
     public static class StackInfo implements Parcelable {
         public int stackId;
-        public Rect bounds;
+        public Rect bounds = new Rect();
         public int[] taskIds;
         public String[] taskNames;
+        public int displayId;
 
         @Override
         public int describeContents() {
@@ -1404,6 +1313,7 @@
             dest.writeInt(bounds.bottom);
             dest.writeIntArray(taskIds);
             dest.writeStringArray(taskNames);
+            dest.writeInt(displayId);
         }
 
         public void readFromParcel(Parcel source) {
@@ -1412,6 +1322,7 @@
                     source.readInt(), source.readInt(), source.readInt(), source.readInt());
             taskIds = source.createIntArray();
             taskNames = source.createStringArray();
+            displayId = source.readInt();
         }
 
         public static final Creator<StackInfo> CREATOR = new Creator<StackInfo>() {
@@ -1435,7 +1346,9 @@
         public String toString(String prefix) {
             StringBuilder sb = new StringBuilder(256);
             sb.append(prefix); sb.append("Stack id="); sb.append(stackId);
-                    sb.append(" bounds="); sb.append(bounds.toShortString()); sb.append("\n");
+                    sb.append(" bounds="); sb.append(bounds.toShortString());
+                    sb.append(" displayId="); sb.append(displayId);
+                    sb.append("\n");
             prefix = prefix + "  ";
             for (int i = 0; i < taskIds.length; ++i) {
                 sb.append(prefix); sb.append("taskId="); sb.append(taskIds[i]);
diff --git a/core/java/android/app/ActivityManagerNative.java b/core/java/android/app/ActivityManagerNative.java
index 74266cc..f0c4c93 100644
--- a/core/java/android/app/ActivityManagerNative.java
+++ b/core/java/android/app/ActivityManagerNative.java
@@ -16,7 +16,7 @@
 
 package android.app;
 
-import android.app.ActivityManager.StackBoxInfo;
+import android.app.ActivityManager.StackInfo;
 import android.content.ComponentName;
 import android.content.IIntentReceiver;
 import android.content.IIntentSender;
@@ -31,6 +31,7 @@
 import android.content.pm.UserInfo;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
+import android.graphics.Rect;
 import android.net.Uri;
 import android.os.Binder;
 import android.os.Bundle;
@@ -614,10 +615,7 @@
         case CREATE_STACK_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             int taskId = data.readInt();
-            int relativeStackId = data.readInt();
-            int position = data.readInt();
-            float weight = data.readFloat();
-            int res = createStack(taskId, relativeStackId, position, weight);
+            int res = createStack(taskId);
             reply.writeNoException();
             reply.writeInt(res);
             return true;
@@ -635,25 +633,26 @@
 
         case RESIZE_STACK_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
-            int stackBoxId = data.readInt();
+            int stackId = data.readInt();
             float weight = data.readFloat();
-            resizeStackBox(stackBoxId, weight);
+            Rect r = Rect.CREATOR.createFromParcel(data);
+            resizeStack(stackId, r);
             reply.writeNoException();
             return true;
         }
 
-        case GET_STACK_BOXES_TRANSACTION: {
+        case GET_ALL_STACK_INFOS_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
-            List<StackBoxInfo> list = getStackBoxes();
+            List<StackInfo> list = getAllStackInfos();
             reply.writeNoException();
             reply.writeTypedList(list);
             return true;
         }
 
-        case GET_STACK_BOX_INFO_TRANSACTION: {
+        case GET_STACK_INFO_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
-            int stackBoxId = data.readInt();
-            StackBoxInfo info = getStackBoxInfo(stackBoxId);
+            int stackId = data.readInt();
+            StackInfo info = getStackInfo(stackId);
             reply.writeNoException();
             if (info != null) {
                 reply.writeInt(1);
@@ -2715,16 +2714,12 @@
         reply.recycle();
     }
     @Override
-    public int createStack(int taskId, int relativeStackBoxId, int position, float weight)
-            throws RemoteException
+    public int createStack(int taskId) throws RemoteException
     {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
         data.writeInterfaceToken(IActivityManager.descriptor);
         data.writeInt(taskId);
-        data.writeInt(relativeStackBoxId);
-        data.writeInt(position);
-        data.writeFloat(weight);
         mRemote.transact(CREATE_STACK_TRANSACTION, data, reply, 0);
         reply.readException();
         int res = reply.readInt();
@@ -2747,44 +2742,44 @@
         reply.recycle();
     }
     @Override
-    public void resizeStackBox(int stackBoxId, float weight) throws RemoteException
+    public void resizeStack(int stackBoxId, Rect r) throws RemoteException
     {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
         data.writeInterfaceToken(IActivityManager.descriptor);
         data.writeInt(stackBoxId);
-        data.writeFloat(weight);
+        r.writeToParcel(data, 0);
         mRemote.transact(RESIZE_STACK_TRANSACTION, data, reply, IBinder.FLAG_ONEWAY);
         reply.readException();
         data.recycle();
         reply.recycle();
     }
     @Override
-    public List<StackBoxInfo> getStackBoxes() throws RemoteException
+    public List<StackInfo> getAllStackInfos() throws RemoteException
     {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
         data.writeInterfaceToken(IActivityManager.descriptor);
-        mRemote.transact(GET_STACK_BOXES_TRANSACTION, data, reply, 0);
+        mRemote.transact(GET_ALL_STACK_INFOS_TRANSACTION, data, reply, 0);
         reply.readException();
-        ArrayList<StackBoxInfo> list = reply.createTypedArrayList(StackBoxInfo.CREATOR);
+        ArrayList<StackInfo> list = reply.createTypedArrayList(StackInfo.CREATOR);
         data.recycle();
         reply.recycle();
         return list;
     }
     @Override
-    public StackBoxInfo getStackBoxInfo(int stackBoxId) throws RemoteException
+    public StackInfo getStackInfo(int stackId) throws RemoteException
     {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
         data.writeInterfaceToken(IActivityManager.descriptor);
-        data.writeInt(stackBoxId);
-        mRemote.transact(GET_STACK_BOX_INFO_TRANSACTION, data, reply, 0);
+        data.writeInt(stackId);
+        mRemote.transact(GET_STACK_INFO_TRANSACTION, data, reply, 0);
         reply.readException();
         int res = reply.readInt();
-        StackBoxInfo info = null;
+        StackInfo info = null;
         if (res != 0) {
-            info = StackBoxInfo.CREATOR.createFromParcel(reply);
+            info = StackInfo.CREATOR.createFromParcel(reply);
         }
         data.recycle();
         reply.recycle();
diff --git a/core/java/android/app/IActivityManager.java b/core/java/android/app/IActivityManager.java
index 77c2ea0..631d9b1 100644
--- a/core/java/android/app/IActivityManager.java
+++ b/core/java/android/app/IActivityManager.java
@@ -18,7 +18,7 @@
 
 import android.app.ActivityManager.RunningTaskInfo;
 import android.app.ActivityManager.RunningServiceInfo;
-import android.app.ActivityManager.StackBoxInfo;
+import android.app.ActivityManager.StackInfo;
 import android.content.ComponentName;
 import android.content.ContentProviderNative;
 import android.content.IContentProvider;
@@ -36,6 +36,7 @@
 import android.content.pm.UserInfo;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
+import android.graphics.Rect;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.Debug;
@@ -117,12 +118,11 @@
     public void moveTaskToBack(int task) throws RemoteException;
     public boolean moveActivityTaskToBack(IBinder token, boolean nonRoot) throws RemoteException;
     public void moveTaskBackwards(int task) throws RemoteException;
-    public int createStack(int taskId, int relativeStackBoxId, int position, float weight)
-            throws RemoteException;
+    public int createStack(int taskId) throws RemoteException;
     public void moveTaskToStack(int taskId, int stackId, boolean toTop) throws RemoteException;
-    public void resizeStackBox(int stackBoxId, float weight) throws RemoteException;
-    public List<StackBoxInfo> getStackBoxes() throws RemoteException;
-    public StackBoxInfo getStackBoxInfo(int stackBoxId) throws RemoteException;
+    public void resizeStack(int stackId, Rect bounds) throws RemoteException;
+    public List<StackInfo> getAllStackInfos() throws RemoteException;
+    public StackInfo getStackInfo(int stackId) throws RemoteException;
     public void setFocusedStack(int stackId) throws RemoteException;
     public int getTaskForActivity(IBinder token, boolean onlyRoot) throws RemoteException;
     /* oneway */
@@ -681,9 +681,9 @@
     int CREATE_STACK_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+167;
     int MOVE_TASK_TO_STACK_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+168;
     int RESIZE_STACK_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+169;
-    int GET_STACK_BOXES_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+170;
+    int GET_ALL_STACK_INFOS_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+170;
     int SET_FOCUSED_STACK_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+171;
-    int GET_STACK_BOX_INFO_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+172;
+    int GET_STACK_INFO_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+172;
     int CONVERT_FROM_TRANSLUCENT_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+173;
     int CONVERT_TO_TRANSLUCENT_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+174;
     int NOTIFY_ACTIVITY_DRAWN_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+175;
diff --git a/services/java/com/android/server/am/ActivityManagerService.java b/services/java/com/android/server/am/ActivityManagerService.java
index 3266ca7..ad30d94 100644
--- a/services/java/com/android/server/am/ActivityManagerService.java
+++ b/services/java/com/android/server/am/ActivityManagerService.java
@@ -29,7 +29,9 @@
 
 import android.app.AppOpsManager;
 import android.appwidget.AppWidgetManager;
+import android.graphics.Rect;
 import android.util.ArrayMap;
+import android.view.Display;
 import com.android.internal.R;
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.app.IAppOpsService;
@@ -52,7 +54,6 @@
 import com.android.server.firewall.IntentFirewall;
 import com.android.server.pm.UserManagerService;
 import com.android.server.wm.AppTransition;
-import com.android.server.wm.StackBox;
 import com.android.server.wm.WindowManagerService;
 import com.google.android.collect.Lists;
 import com.google.android.collect.Maps;
@@ -68,7 +69,6 @@
 import android.app.Activity;
 import android.app.ActivityManager;
 import android.app.ActivityManager.RunningTaskInfo;
-import android.app.ActivityManager.StackBoxInfo;
 import android.app.ActivityManager.StackInfo;
 import android.app.ActivityManagerNative;
 import android.app.ActivityOptions;
@@ -1770,7 +1770,7 @@
     public void setWindowManager(WindowManagerService wm) {
         mWindowManager = wm;
         mStackSupervisor.setWindowManager(wm);
-        wm.createStack(HOME_STACK_ID, -1, StackBox.TASK_STACK_GOES_OVER, 1.0f);
+        wm.createStack(HOME_STACK_ID, Display.DEFAULT_DISPLAY);
     }
 
     public void startObservingNativeCrashes() {
@@ -7100,16 +7100,15 @@
     }
 
     @Override
-    public int createStack(int taskId, int relativeStackBoxId, int position, float weight) {
+    public int createStack(int taskId) {
         enforceCallingPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS,
                 "createStack()");
-        if (DEBUG_STACK) Slog.d(TAG, "createStack: taskId=" + taskId + " relStackBoxId=" +
-                relativeStackBoxId + " position=" + position + " weight=" + weight);
+        if (DEBUG_STACK) Slog.d(TAG, "createStack: taskId=" + taskId);
         synchronized (this) {
             long ident = Binder.clearCallingIdentity();
             try {
                 int stackId = mStackSupervisor.createStack();
-                mWindowManager.createStack(stackId, relativeStackBoxId, position, weight);
+                mWindowManager.createStack(stackId, Display.DEFAULT_DISPLAY);
                 if (taskId > 0) {
                     moveTaskToStack(taskId, stackId, true);
                 }
@@ -7141,99 +7140,40 @@
     }
 
     @Override
-    public void resizeStackBox(int stackBoxId, float weight) {
+    public void resizeStack(int stackBoxId, Rect bounds) {
         enforceCallingPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS,
                 "resizeStackBox()");
         long ident = Binder.clearCallingIdentity();
         try {
-            mWindowManager.resizeStackBox(stackBoxId, weight);
+            mWindowManager.resizeStack(stackBoxId, bounds);
         } finally {
             Binder.restoreCallingIdentity(ident);
         }
     }
 
-    private ArrayList<StackInfo> getStacks() {
-        synchronized (this) {
-            ArrayList<ActivityManager.StackInfo> list = new ArrayList<ActivityManager.StackInfo>();
-            ArrayList<ActivityStack> stacks = mStackSupervisor.getStacks();
-            for (ActivityStack stack : stacks) {
-                ActivityManager.StackInfo stackInfo = new ActivityManager.StackInfo();
-                int stackId = stack.mStackId;
-                stackInfo.stackId = stackId;
-                stackInfo.bounds = mWindowManager.getStackBounds(stackId);
-                ArrayList<TaskRecord> tasks = stack.getAllTasks();
-                final int numTasks = tasks.size();
-                int[] taskIds = new int[numTasks];
-                String[] taskNames = new String[numTasks];
-                for (int i = 0; i < numTasks; ++i) {
-                    final TaskRecord task = tasks.get(i);
-                    taskIds[i] = task.taskId;
-                    taskNames[i] = task.origActivity != null ? task.origActivity.flattenToString()
-                            : task.realActivity != null ? task.realActivity.flattenToString()
-                            : task.getTopActivity() != null ? task.getTopActivity().packageName
-                            : "unknown";
-                }
-                stackInfo.taskIds = taskIds;
-                stackInfo.taskNames = taskNames;
-                list.add(stackInfo);
-            }
-            return list;
-        }
-    }
-
-    private void addStackInfoToStackBoxInfo(StackBoxInfo stackBoxInfo, List<StackInfo> stackInfos) {
-        final int stackId = stackBoxInfo.stackId;
-        if (stackId >= 0) {
-            for (StackInfo stackInfo : stackInfos) {
-                if (stackId == stackInfo.stackId) {
-                    stackBoxInfo.stack = stackInfo;
-                    stackInfos.remove(stackInfo);
-                    return;
-                }
-            }
-        } else {
-            addStackInfoToStackBoxInfo(stackBoxInfo.children[0], stackInfos);
-            addStackInfoToStackBoxInfo(stackBoxInfo.children[1], stackInfos);
-        }
-    }
-
     @Override
-    public List<StackBoxInfo> getStackBoxes() {
+    public List<StackInfo> getAllStackInfos() {
         enforceCallingPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS,
                 "getStackBoxes()");
         long ident = Binder.clearCallingIdentity();
         try {
-            List<StackBoxInfo> stackBoxInfos = mWindowManager.getStackBoxInfos();
             synchronized (this) {
-                List<StackInfo> stackInfos = getStacks();
-                for (StackBoxInfo stackBoxInfo : stackBoxInfos) {
-                    addStackInfoToStackBoxInfo(stackBoxInfo, stackInfos);
-                }
+                return mStackSupervisor.getAllStackInfos();
             }
-            return stackBoxInfos;
         } finally {
             Binder.restoreCallingIdentity(ident);
         }
     }
 
     @Override
-    public StackBoxInfo getStackBoxInfo(int stackBoxId) {
+    public StackInfo getStackInfo(int stackId) {
         enforceCallingPermission(android.Manifest.permission.MANAGE_ACTIVITY_STACKS,
-                "getStackBoxInfo()");
+                "getStackInfo()");
         long ident = Binder.clearCallingIdentity();
         try {
-            List<StackBoxInfo> stackBoxInfos = mWindowManager.getStackBoxInfos();
-            StackBoxInfo info = null;
             synchronized (this) {
-                List<StackInfo> stackInfos = getStacks();
-                for (StackBoxInfo stackBoxInfo : stackBoxInfos) {
-                    addStackInfoToStackBoxInfo(stackBoxInfo, stackInfos);
-                    if (stackBoxInfo.stackBoxId == stackBoxId) {
-                        info = stackBoxInfo;
-                    }
-                }
+                return mStackSupervisor.getStackInfo(stackId);
             }
-            return info;
         } finally {
             Binder.restoreCallingIdentity(ident);
         }
diff --git a/services/java/com/android/server/am/ActivityStackSupervisor.java b/services/java/com/android/server/am/ActivityStackSupervisor.java
index 04617af..1f0a4cd 100644
--- a/services/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/java/com/android/server/am/ActivityStackSupervisor.java
@@ -34,6 +34,7 @@
 
 import android.app.Activity;
 import android.app.ActivityManager;
+import android.app.ActivityManager.StackInfo;
 import android.app.ActivityOptions;
 import android.app.AppGlobals;
 import android.app.IActivityManager;
@@ -70,11 +71,11 @@
 import android.util.Slog;
 import android.util.SparseIntArray;
 
+import android.view.Display;
 import com.android.internal.app.HeavyWeightSwitcherActivity;
 import com.android.internal.os.TransferPipe;
 import com.android.server.am.ActivityManagerService.PendingActivityLaunch;
 import com.android.server.am.ActivityStack.ActivityState;
-import com.android.server.wm.StackBox;
 import com.android.server.wm.WindowManagerService;
 
 import java.io.FileDescriptor;
@@ -1289,8 +1290,7 @@
             }
 
             // Time to create the first app stack for this user.
-            int stackId =
-                    mService.createStack(-1, HOME_STACK_ID, StackBox.TASK_STACK_GOES_OVER, 1.0f);
+            int stackId = mService.createStack(-1);
             if (DEBUG_FOCUS || DEBUG_STACK) Slog.d(TAG, "adjustStackFocus: New stack r=" + r +
                     " stackId=" + stackId);
             mFocusedStack = getStack(stackId);
@@ -2645,4 +2645,43 @@
             }
         }
     }
+
+    StackInfo getStackInfo(ActivityStack stack) {
+        StackInfo info = new StackInfo();
+        mWindowManager.getStackBounds(stack.mStackId, info.bounds);
+        info.displayId = Display.DEFAULT_DISPLAY;
+        info.stackId = stack.mStackId;
+
+        ArrayList<TaskRecord> tasks = stack.getAllTasks();
+        final int numTasks = tasks.size();
+        int[] taskIds = new int[numTasks];
+        String[] taskNames = new String[numTasks];
+        for (int i = 0; i < numTasks; ++i) {
+            final TaskRecord task = tasks.get(i);
+            taskIds[i] = task.taskId;
+            taskNames[i] = task.origActivity != null ? task.origActivity.flattenToString()
+                    : task.realActivity != null ? task.realActivity.flattenToString()
+                    : task.getTopActivity() != null ? task.getTopActivity().packageName
+                    : "unknown";
+        }
+        info.taskIds = taskIds;
+        info.taskNames = taskNames;
+        return info;
+    }
+
+    StackInfo getStackInfo(int stackId) {
+        ActivityStack stack = getStack(stackId);
+        if (stack != null) {
+            return getStackInfo(stack);
+        }
+        return null;
+    }
+
+    ArrayList<StackInfo> getAllStackInfos() {
+        ArrayList<StackInfo> list = new ArrayList<StackInfo>();
+        for (int ndx = mStacks.size() - 1; ndx >= 0; --ndx) {
+            list.add(getStackInfo(mStacks.get(ndx)));
+        }
+        return list;
+    }
 }
diff --git a/services/java/com/android/server/wm/DimLayer.java b/services/java/com/android/server/wm/DimLayer.java
index c189ddd..978d5b7 100644
--- a/services/java/com/android/server/wm/DimLayer.java
+++ b/services/java/com/android/server/wm/DimLayer.java
@@ -166,7 +166,7 @@
 
         final int dw, dh;
         final float xPos, yPos;
-        if (mStack.hasSibling()) {
+        if (!mStack.isFullscreen()) {
             dw = mBounds.width();
             dh = mBounds.height();
             xPos = mBounds.left;
diff --git a/services/java/com/android/server/wm/DisplayContent.java b/services/java/com/android/server/wm/DisplayContent.java
index d358b4c..4352ece 100644
--- a/services/java/com/android/server/wm/DisplayContent.java
+++ b/services/java/com/android/server/wm/DisplayContent.java
@@ -21,10 +21,8 @@
 import static com.android.server.wm.WindowManagerService.DEBUG_VISIBILITY;
 import static com.android.server.wm.WindowManagerService.TAG;
 
-import android.app.ActivityManager.StackBoxInfo;
 import android.graphics.Rect;
 import android.graphics.Region;
-import android.os.Debug;
 import android.util.EventLog;
 import android.util.Slog;
 import android.view.Display;
@@ -74,6 +72,7 @@
     private final Display mDisplay;
 
     Rect mBaseDisplayRect = new Rect();
+    Rect mContentRect = new Rect();
 
     // Accessed directly by all users.
     boolean layoutNeeded;
@@ -92,11 +91,12 @@
      */
     final AppTokenList mExitingAppTokens = new AppTokenList();
 
-    /** Array containing the home StackBox and possibly one more which would contain apps. Array
+    /** Array containing all TaskStacks on this display.  Array
      * is stored in display order with the current bottom stack at 0. */
-    private ArrayList<StackBox> mStackBoxes = new ArrayList<StackBox>();
+    private ArrayList<TaskStack> mStacks = new ArrayList<TaskStack>();
 
-    /** True when the home StackBox is at the top of mStackBoxes, false otherwise. */
+    /** A special TaskStack with id==HOME_STACK_ID that moves to the bottom whenever any TaskStack
+     * (except a future lockscreen TaskStack) moves to the top. */
     private TaskStack mHomeStack = null;
 
     /** Detect user tapping outside of current focused stack bounds .*/
@@ -123,13 +123,6 @@
         display.getDisplayInfo(mDisplayInfo);
         isDefaultDisplay = mDisplayId == Display.DEFAULT_DISPLAY;
         mService = service;
-
-        StackBox newBox = new StackBox(service, this, null);
-        mStackBoxes.add(newBox);
-        TaskStack newStack = new TaskStack(service, HOME_STACK_ID, this);
-        newStack.mStackBox = newBox;
-        newBox.mStack = newStack;
-        mHomeStack = newStack;
     }
 
     int getDisplayId() {
@@ -155,10 +148,6 @@
         return mDisplay.hasAccess(uid);
     }
 
-    boolean homeOnTop() {
-        return mStackBoxes.get(0).mStack != mHomeStack;
-    }
-
     public boolean isPrivate() {
         return (mDisplay.getFlags() & Display.FLAG_PRIVATE) != 0;
     }
@@ -205,7 +194,18 @@
     }
 
     void updateDisplayInfo() {
+        // Save old size.
+        int oldWidth = mDisplayInfo.logicalWidth;
+        int oldHeight = mDisplayInfo.logicalHeight;
         mDisplay.getDisplayInfo(mDisplayInfo);
+
+        for (int i = mStacks.size() - 1; i >= 0; --i) {
+            final TaskStack stack = mStacks.get(i);
+            if (!stack.isFullscreen()) {
+                stack.resizeBounds(oldWidth, oldHeight, mDisplayInfo.logicalWidth,
+                        mDisplayInfo.logicalHeight);
+            }
+        }
     }
 
     void getLogicalDisplayRect(Rect out) {
@@ -227,159 +227,58 @@
         return count;
     }
 
-    /** Refer to {@link WindowManagerService#createStack(int, int, int, float)} */
-    TaskStack createStack(int stackId, int relativeStackBoxId, int position, float weight) {
-        TaskStack newStack = null;
-        if (DEBUG_STACK) Slog.d(TAG, "createStack: stackId=" + stackId + " relativeStackBoxId="
-                + relativeStackBoxId + " position=" + position + " weight=" + weight);
+    /** Refer to {@link WindowManagerService#createStack(int, int)} */
+    TaskStack createStack(int stackId) {
+        if (DEBUG_STACK) Slog.d(TAG, "createStack: stackId=" + stackId);
+        TaskStack newStack = new TaskStack(mService, stackId, this);
         if (stackId == HOME_STACK_ID) {
-            if (mStackBoxes.size() != 1) {
+            if (mHomeStack != null) {
                 throw new IllegalArgumentException("createStack: HOME_STACK_ID (0) not first.");
             }
-            newStack = mHomeStack;
-        } else {
-            int stackBoxNdx;
-            for (stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-                final StackBox box = mStackBoxes.get(stackBoxNdx);
-                if (position == StackBox.TASK_STACK_GOES_OVER
-                        || position == StackBox.TASK_STACK_GOES_UNDER) {
-                    // Position indicates a new box is added at top level only.
-                    if (box.contains(relativeStackBoxId)) {
-                        StackBox newBox = new StackBox(mService, this, null);
-                        newStack = new TaskStack(mService, stackId, this);
-                        newStack.mStackBox = newBox;
-                        newBox.mStack = newStack;
-                        final int offset = position == StackBox.TASK_STACK_GOES_OVER ? 1 : 0;
-                        if (DEBUG_STACK) Slog.d(TAG, "createStack: inserting stack at " +
-                                (stackBoxNdx + offset));
-                        mStackBoxes.add(stackBoxNdx + offset, newBox);
-                        break;
-                    }
-                } else {
-                    // Remaining position values indicate a box must be split.
-                    newStack = box.split(stackId, relativeStackBoxId, position, weight);
-                    if (newStack != null) {
-                        break;
-                    }
-                }
-            }
-            if (stackBoxNdx < 0) {
-                throw new IllegalArgumentException("createStack: stackBoxId " + relativeStackBoxId
-                        + " not found.");
-            }
+            mHomeStack = newStack;
         }
-        if (newStack != null) {
-            layoutNeeded = true;
-        }
-        EventLog.writeEvent(EventLogTags.WM_STACK_CREATED, stackId, relativeStackBoxId, position,
-                (int)(weight * 100 + 0.5));
+        mStacks.add(newStack);
+        layoutNeeded = true;
         return newStack;
     }
 
-    /** Refer to {@link WindowManagerService#resizeStackBox(int, float)} */
-    boolean resizeStack(int stackBoxId, float weight) {
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            final StackBox box = mStackBoxes.get(stackBoxNdx);
-            if (box.resize(stackBoxId, weight)) {
-                layoutNeeded = true;
+    void moveStack(TaskStack stack, boolean toTop) {
+        mStacks.remove(stack);
+        mStacks.add(toTop ? mStacks.size() : 0, stack);
+    }
+
+    TaskStack topStack() {
+        return mStacks.get(mStacks.size() - 1);
+    }
+
+    /**
+     * Propagate the new bounds to all child stacks.
+     * @param contentRect The bounds to apply at the top level.
+     */
+    void resize(Rect contentRect) {
+        mContentRect.set(contentRect);
+    }
+
+    boolean getStackBounds(int stackId, Rect bounds) {
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            final TaskStack stack = mStacks.get(stackNdx);
+            if (stackId == stack.mStackId) {
+                bounds.set(stack.mBounds);
                 return true;
             }
         }
         return false;
     }
 
-    void addStackBox(StackBox box, boolean toTop) {
-        if (mStackBoxes.size() >= 2) {
-            throw new RuntimeException("addStackBox: Too many toplevel StackBoxes!");
-        }
-        mStackBoxes.add(toTop ? mStackBoxes.size() : 0, box);
-    }
-
-    void removeStackBox(StackBox box) {
-        if (DEBUG_STACK) Slog.d(TAG, "removeStackBox: box=" + box);
-        final TaskStack stack = box.mStack;
-        if (stack != null && stack.mStackId == HOME_STACK_ID) {
-            // Never delete the home stack, even if it is empty.
-            if (DEBUG_STACK) Slog.d(TAG, "removeStackBox: Not deleting home stack.");
-            return;
-        }
-        mStackBoxes.remove(box);
-    }
-
-    StackBoxInfo getStackBoxInfo(StackBox box) {
-        StackBoxInfo info = new StackBoxInfo();
-        info.stackBoxId = box.mStackBoxId;
-        info.weight = box.mWeight;
-        info.vertical = box.mVertical;
-        info.bounds = new Rect(box.mBounds);
-        if (box.mStack != null) {
-            info.stackId = box.mStack.mStackId;
-            // ActivityManagerService will fill in the StackInfo.
-        } else {
-            info.stackId = -1;
-            info.children = new StackBoxInfo[2];
-            info.children[0] = getStackBoxInfo(box.mFirst);
-            info.children[1] = getStackBoxInfo(box.mSecond);
-        }
-        return info;
-    }
-
-    ArrayList<StackBoxInfo> getStackBoxInfos() {
-        ArrayList<StackBoxInfo> list = new ArrayList<StackBoxInfo>();
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            list.add(getStackBoxInfo(mStackBoxes.get(stackBoxNdx)));
-        }
-        return list;
-    }
-
-    /**
-     * Move the home StackBox to the top or bottom of mStackBoxes. That is the only place
-     * it is allowed to be. This is a nop if the home StackBox is already in the correct position.
-     * @param toTop Move home to the top of mStackBoxes if true, to the bottom if false.
-     * @return true if a change was made, false otherwise.
-     */
-    boolean moveHomeStackBox(boolean toTop) {
-        if (DEBUG_STACK) Slog.d(TAG, "moveHomeStackBox: toTop=" + toTop + " Callers=" +
-                Debug.getCallers(4));
-        EventLog.writeEvent(EventLogTags.WM_HOME_STACK_MOVED, toTop ? 1 : 0);
-        switch (mStackBoxes.size()) {
-            case 0: throw new RuntimeException("moveHomeStackBox: No home StackBox!");
-            case 1: return false; // Only the home StackBox exists.
-            case 2:
-                if (homeOnTop() ^ toTop) {
-                    mStackBoxes.add(mStackBoxes.remove(0));
-                    return true;
-                }
-                return false;
-            default: throw new RuntimeException("moveHomeStackBox: Too many toplevel StackBoxes!");
-        }
-    }
-
-    /**
-     * Propagate the new bounds to all child stack boxes, applying weights as we move down.
-     * @param contentRect The bounds to apply at the top level.
-     */
-    boolean setStackBoxSize(Rect contentRect) {
-        boolean change = false;
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            change |= mStackBoxes.get(stackBoxNdx).setStackBoxSizes(contentRect, true);
-        }
-        return change;
-    }
-
-    Rect getStackBounds(int stackId) {
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            Rect bounds = mStackBoxes.get(stackBoxNdx).getStackBounds(stackId);
-            if (bounds != null) {
-                return bounds;
+    int stackIdFromPoint(int x, int y) {
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            final TaskStack stack = mStacks.get(stackNdx);
+            stack.getBounds(mTmpRect);
+            if (mTmpRect.contains(x, y)) {
+                return stack.mStackId;
             }
         }
-        return null;
-    }
-
-    int stackIdFromPoint(int x, int y) {
-        StackBox topBox = mStackBoxes.get(mStackBoxes.size() - 1);
-        return topBox.stackIdFromPoint(x, y);
+        return -1;
     }
 
     void setTouchExcludeRegion(TaskStack focusedStack) {
@@ -408,48 +307,48 @@
             }
         }
 
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            mStackBoxes.get(stackBoxNdx).switchUserStacks(newUserId);
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            mStacks.get(stackNdx).switchUser(newUserId);
         }
     }
 
     void resetAnimationBackgroundAnimator() {
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            mStackBoxes.get(stackBoxNdx).resetAnimationBackgroundAnimator();
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            mStacks.get(stackNdx).resetAnimationBackgroundAnimator();
         }
     }
 
     boolean animateDimLayers() {
         boolean result = false;
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            result |= mStackBoxes.get(stackBoxNdx).animateDimLayers();
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            result |= mStacks.get(stackNdx).animateDimLayers();
         }
         return result;
     }
 
     void resetDimming() {
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            mStackBoxes.get(stackBoxNdx).resetDimming();
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            mStacks.get(stackNdx).resetDimmingTag();
         }
     }
 
     boolean isDimming() {
         boolean result = false;
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            result |= mStackBoxes.get(stackBoxNdx).isDimming();
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            result |= mStacks.get(stackNdx).isDimming();
         }
         return result;
     }
 
     void stopDimmingIfNeeded() {
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            mStackBoxes.get(stackBoxNdx).stopDimmingIfNeeded();
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            mStacks.get(stackNdx).stopDimmingIfNeeded();
         }
     }
 
     void close() {
-        for (int stackBoxNdx = mStackBoxes.size() - 1; stackBoxNdx >= 0; --stackBoxNdx) {
-            mStackBoxes.get(stackBoxNdx).close();
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            mStacks.get(stackNdx).close();
         }
     }
 
@@ -477,9 +376,10 @@
             pw.print("-"); pw.print(mDisplayInfo.largestNominalAppWidth);
             pw.print("x"); pw.println(mDisplayInfo.largestNominalAppHeight);
             pw.print(subPrefix); pw.print("layoutNeeded="); pw.println(layoutNeeded);
-        for (int boxNdx = 0; boxNdx < mStackBoxes.size(); ++boxNdx) {
-            pw.print(prefix); pw.print("StackBox #"); pw.println(boxNdx);
-            mStackBoxes.get(boxNdx).dump(prefix + "  ", pw);
+        for (int stackNdx = mStacks.size() - 1; stackNdx >= 0; --stackNdx) {
+            final TaskStack stack = mStacks.get(stackNdx);
+            pw.print(prefix); pw.print("mStacks[" + stackNdx + "]"); pw.println(stack.mStackId);
+            stack.dump(prefix + "  ", pw);
         }
         int ndx = numTokens();
         if (ndx > 0) {
diff --git a/services/java/com/android/server/wm/FocusedStackFrame.java b/services/java/com/android/server/wm/FocusedStackFrame.java
index cc48b86..f1f5fe8 100644
--- a/services/java/com/android/server/wm/FocusedStackFrame.java
+++ b/services/java/com/android/server/wm/FocusedStackFrame.java
@@ -41,7 +41,7 @@
     private final SurfaceControl mSurfaceControl;
     private final Surface mSurface = new Surface();
     private final Rect mLastBounds = new Rect();
-    private final Rect mBounds = new Rect();
+    final Rect mBounds = new Rect();
     private final Rect mTmpDrawRect = new Rect();
 
     public FocusedStackFrame(Display display, SurfaceSession session) {
@@ -131,9 +131,9 @@
         }
     }
 
-    public void setBounds(Rect bounds) {
-        if (false && DEBUG_STACK) Slog.i(TAG, "setBounds: bounds=" + bounds);
-        mBounds.set(bounds);
+    public void setBounds(TaskStack stack) {
+        stack.getBounds(mBounds);
+        if (false && DEBUG_STACK) Slog.i(TAG, "setBounds: bounds=" + mBounds);
     }
 
     public void setLayer(int layer) {
diff --git a/services/java/com/android/server/wm/InputMonitor.java b/services/java/com/android/server/wm/InputMonitor.java
index 3d2ec45..803b9ac 100644
--- a/services/java/com/android/server/wm/InputMonitor.java
+++ b/services/java/com/android/server/wm/InputMonitor.java
@@ -58,6 +58,8 @@
     private final Object mInputDevicesReadyMonitor = new Object();
     private boolean mInputDevicesReady;
 
+    Rect mTmpRect = new Rect();
+
     public InputMonitor(WindowManagerService service) {
         mService = service;
     }
@@ -175,7 +177,8 @@
         if (modal && child.mAppToken != null) {
             // Limit the outer touch to the activity stack region.
             flags |= WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL;
-            inputWindowHandle.touchableRegion.set(child.getStackBounds());
+            child.getStackBounds(mTmpRect);
+            inputWindowHandle.touchableRegion.set(mTmpRect);
         } else {
             // Not modal or full screen modal
             child.getTouchableRegion(inputWindowHandle.touchableRegion);
diff --git a/services/java/com/android/server/wm/StackBox.java b/services/java/com/android/server/wm/StackBox.java
deleted file mode 100644
index d351925..0000000
--- a/services/java/com/android/server/wm/StackBox.java
+++ /dev/null
@@ -1,414 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.server.wm;
-
-import android.graphics.Rect;
-import android.util.Slog;
-
-import static com.android.server.am.ActivityStackSupervisor.HOME_STACK_ID;
-import static com.android.server.wm.WindowManagerService.DEBUG_STACK;
-import static com.android.server.wm.WindowManagerService.TAG;
-
-import java.io.PrintWriter;
-
-public class StackBox {
-    /** Used with {@link WindowManagerService#createStack}. Dependent on Configuration LTR/RTL. */
-    public static final int TASK_STACK_GOES_BEFORE = 0;
-    /** Used with {@link WindowManagerService#createStack}. Dependent on Configuration LTR/RTL. */
-    public static final int TASK_STACK_GOES_AFTER = 1;
-    /** Used with {@link WindowManagerService#createStack}. Horizontal to left of. */
-    public static final int TASK_STACK_TO_LEFT_OF = 2;
-    /** Used with {@link WindowManagerService#createStack}. Horizontal to right of. */
-    public static final int TASK_STACK_TO_RIGHT_OF = 3;
-    /** Used with {@link WindowManagerService#createStack}. Vertical: lower t/b Rect values. */
-    public static final int TASK_STACK_GOES_ABOVE = 4;
-    /** Used with {@link WindowManagerService#createStack}. Vertical: higher t/b Rect values. */
-    public static final int TASK_STACK_GOES_BELOW = 5;
-    /** Used with {@link WindowManagerService#createStack}. Put on a higher layer on display. */
-    public static final int TASK_STACK_GOES_OVER = 6;
-    /** Used with {@link WindowManagerService#createStack}. Put on a lower layer on display. */
-    public static final int TASK_STACK_GOES_UNDER = 7;
-
-    static int sCurrentBoxId = 0;
-
-    /** Unique id for this box */
-    final int mStackBoxId;
-
-    /** The service */
-    final WindowManagerService mService;
-
-    /** The display this box sits in. */
-    final DisplayContent mDisplayContent;
-
-    /** Non-null indicates this is mFirst or mSecond of a parent StackBox. Null indicates this
-     * is this entire size of mDisplayContent. */
-    StackBox mParent;
-
-    /** First child, this is null exactly when mStack is non-null. */
-    StackBox mFirst;
-
-    /** Second child, this is null exactly when mStack is non-null. */
-    StackBox mSecond;
-
-    /** Stack of Tasks, this is null exactly when mFirst and mSecond are non-null. */
-    TaskStack mStack;
-
-    /** Content limits relative to the DisplayContent this sits in. */
-    Rect mBounds = new Rect();
-
-    /** Relative orientation of mFirst and mSecond. */
-    boolean mVertical;
-
-    /** Fraction of mBounds to devote to mFirst, remainder goes to mSecond */
-    float mWeight;
-
-    /** Dirty flag. Something inside this or some descendant of this has changed. */
-    boolean layoutNeeded;
-
-    /** True if this StackBox sits below the Status Bar. */
-    boolean mUnderStatusBar;
-
-    /** Used to keep from reallocating a temporary Rect for propagating bounds to child boxes */
-    Rect mTmpRect = new Rect();
-
-    StackBox(WindowManagerService service, DisplayContent displayContent, StackBox parent) {
-        synchronized (StackBox.class) {
-            mStackBoxId = sCurrentBoxId++;
-        }
-
-        mService = service;
-        mDisplayContent = displayContent;
-        mParent = parent;
-    }
-
-    /** Propagate #layoutNeeded bottom up. */
-    void makeDirty() {
-        layoutNeeded = true;
-        if (mParent != null) {
-            mParent.makeDirty();
-        }
-    }
-
-    /**
-     * Determine if a particular StackBox is this one or a descendant of this one.
-     * @param stackBoxId The StackBox being searched for.
-     * @return true if the specified StackBox matches this or one of its descendants.
-     */
-    boolean contains(int stackBoxId) {
-        return mStackBoxId == stackBoxId ||
-                (mStack == null &&  (mFirst.contains(stackBoxId) || mSecond.contains(stackBoxId)));
-    }
-
-    /**
-     * Return the stackId of the stack that intersects the passed point.
-     * @param x coordinate of point.
-     * @param y coordinate of point.
-     * @return -1 if point is outside of mBounds, otherwise the stackId of the containing stack.
-     */
-    int stackIdFromPoint(int x, int y) {
-        if (!mBounds.contains(x, y)) {
-            return -1;
-        }
-        if (mStack != null) {
-            return mStack.mStackId;
-        }
-        int stackId = mFirst.stackIdFromPoint(x, y);
-        if (stackId >= 0) {
-            return stackId;
-        }
-        return mSecond.stackIdFromPoint(x, y);
-    }
-
-    /** Determine if this StackBox is the first child or second child.
-     * @return true if this is the first child.
-     */
-    boolean isFirstChild() {
-        return mParent != null && mParent.mFirst == this;
-    }
-
-    /** Returns the bounds of the specified TaskStack if it is contained in this StackBox.
-     * @param stackId the TaskStack to find the bounds of.
-     * @return a new Rect with the bounds of stackId if it is within this StackBox, null otherwise.
-     */
-    Rect getStackBounds(int stackId) {
-        if (mStack != null) {
-            return mStack.mStackId == stackId ? new Rect(mBounds) : null;
-        }
-        Rect bounds = mFirst.getStackBounds(stackId);
-        if (bounds != null) {
-            return bounds;
-        }
-        return mSecond.getStackBounds(stackId);
-    }
-
-    /**
-     * Create a new TaskStack relative to a specified one by splitting the StackBox containing
-     * the specified TaskStack into two children. The size and position each of the new StackBoxes
-     * is determined by the passed parameters.
-     * @param stackId The id of the new TaskStack to create.
-     * @param relativeStackBoxId The id of the StackBox to place the new TaskStack next to.
-     * @param position One of the static TASK_STACK_GOES_xxx positions defined in this class.
-     * @param weight The percentage size of the parent StackBox to devote to the new TaskStack.
-     * @return The new TaskStack.
-     */
-    TaskStack split(int stackId, int relativeStackBoxId, int position, float weight) {
-        if (mStackBoxId != relativeStackBoxId) {
-            // This is not the targeted StackBox.
-            if (mStack != null) {
-                return null;
-            }
-            // Propagate the split to see if the targeted StackBox is in either sub box.
-            TaskStack stack = mFirst.split(stackId, relativeStackBoxId, position, weight);
-            if (stack != null) {
-                return stack;
-            }
-            return mSecond.split(stackId, relativeStackBoxId, position, weight);
-        }
-
-        // Found it!
-        TaskStack stack = new TaskStack(mService, stackId, mDisplayContent);
-        TaskStack firstStack;
-        TaskStack secondStack;
-        if (position == TASK_STACK_GOES_BEFORE) {
-            // TODO: Test Configuration here for LTR/RTL.
-            position = TASK_STACK_TO_LEFT_OF;
-        } else if (position == TASK_STACK_GOES_AFTER) {
-            // TODO: Test Configuration here for LTR/RTL.
-            position = TASK_STACK_TO_RIGHT_OF;
-        }
-        switch (position) {
-            default:
-            case TASK_STACK_TO_LEFT_OF:
-            case TASK_STACK_TO_RIGHT_OF:
-                mVertical = false;
-                if (position == TASK_STACK_TO_LEFT_OF) {
-                    mWeight = weight;
-                    firstStack = stack;
-                    secondStack = mStack;
-                } else {
-                    mWeight = 1.0f - weight;
-                    firstStack = mStack;
-                    secondStack = stack;
-                }
-                break;
-            case TASK_STACK_GOES_ABOVE:
-            case TASK_STACK_GOES_BELOW:
-                mVertical = true;
-                if (position == TASK_STACK_GOES_ABOVE) {
-                    mWeight = weight;
-                    firstStack = stack;
-                    secondStack = mStack;
-                } else {
-                    mWeight = 1.0f - weight;
-                    firstStack = mStack;
-                    secondStack = stack;
-                }
-                break;
-        }
-
-        mFirst = new StackBox(mService, mDisplayContent, this);
-        firstStack.mStackBox = mFirst;
-        mFirst.mStack = firstStack;
-
-        mSecond = new StackBox(mService, mDisplayContent, this);
-        secondStack.mStackBox = mSecond;
-        mSecond.mStack = secondStack;
-
-        mStack = null;
-        return stack;
-    }
-
-    /** Return the stackId of the first mFirst StackBox with a non-null mStack */
-    int getStackId() {
-        if (mStack != null) {
-            return mStack.mStackId;
-        }
-        return mFirst.getStackId();
-    }
-
-    /** Remove this box and propagate its sibling's content up to their parent.
-     * @return The first stackId of the resulting StackBox. */
-    int remove() {
-        mDisplayContent.layoutNeeded = true;
-
-        if (mParent == null) {
-            // This is the top-plane stack.
-            if (DEBUG_STACK) Slog.i(TAG, "StackBox.remove: removing top plane.");
-            mDisplayContent.removeStackBox(this);
-            return HOME_STACK_ID;
-        }
-
-        StackBox sibling = isFirstChild() ? mParent.mSecond : mParent.mFirst;
-        StackBox grandparent = mParent.mParent;
-        sibling.mParent = grandparent;
-        if (grandparent == null) {
-            // mParent is a top-plane stack. Now sibling will be.
-            if (DEBUG_STACK) Slog.i(TAG, "StackBox.remove: grandparent null");
-            mDisplayContent.removeStackBox(mParent);
-            mDisplayContent.addStackBox(sibling, true);
-        } else {
-            if (DEBUG_STACK) Slog.i(TAG, "StackBox.remove: grandparent getting sibling");
-            if (mParent.isFirstChild()) {
-                grandparent.mFirst = sibling;
-            } else {
-                grandparent.mSecond = sibling;
-            }
-        }
-        return sibling.getStackId();
-    }
-
-    boolean resize(int stackBoxId, float weight) {
-        if (mStackBoxId != stackBoxId) {
-            return mStack == null &&
-                    (mFirst.resize(stackBoxId, weight) || mSecond.resize(stackBoxId, weight));
-        }
-        // Don't change weight on topmost stack.
-        if (mParent != null) {
-            mParent.mWeight = isFirstChild() ? weight : 1.0f - weight;
-        }
-        return true;
-    }
-
-    /** If this is a terminal StackBox (contains a TaskStack) set the bounds.
-     * @param bounds The rectangle to set the bounds to.
-     * @param underStatusBar True if the StackBox is directly below the Status Bar.
-     * @return True if the bounds changed, false otherwise. */
-    boolean setStackBoxSizes(Rect bounds, boolean underStatusBar) {
-        boolean change = false;
-        if (mUnderStatusBar != underStatusBar) {
-            change = true;
-            mUnderStatusBar = underStatusBar;
-        }
-        if (mStack != null) {
-            change |= !mBounds.equals(bounds);
-            if (change) {
-                mBounds.set(bounds);
-                mStack.setBounds(bounds, underStatusBar);
-            }
-        } else {
-            mTmpRect.set(bounds);
-            if (mVertical) {
-                final int height = bounds.height();
-                int firstHeight = (int)(height * mWeight);
-                mTmpRect.bottom = bounds.top + firstHeight;
-                change |= mFirst.setStackBoxSizes(mTmpRect, underStatusBar);
-                mTmpRect.top = mTmpRect.bottom;
-                mTmpRect.bottom = bounds.top + height;
-                change |= mSecond.setStackBoxSizes(mTmpRect, false);
-            } else {
-                final int width = bounds.width();
-                int firstWidth = (int)(width * mWeight);
-                mTmpRect.right = bounds.left + firstWidth;
-                change |= mFirst.setStackBoxSizes(mTmpRect, underStatusBar);
-                mTmpRect.left = mTmpRect.right;
-                mTmpRect.right = bounds.left + width;
-                change |= mSecond.setStackBoxSizes(mTmpRect, underStatusBar);
-            }
-        }
-        return change;
-    }
-
-    void resetAnimationBackgroundAnimator() {
-        if (mStack != null) {
-            mStack.resetAnimationBackgroundAnimator();
-            return;
-        }
-        mFirst.resetAnimationBackgroundAnimator();
-        mSecond.resetAnimationBackgroundAnimator();
-    }
-
-    boolean animateDimLayers() {
-        if (mStack != null) {
-            return mStack.animateDimLayers();
-        }
-        boolean result = mFirst.animateDimLayers();
-        result |= mSecond.animateDimLayers();
-        return result;
-    }
-
-    void resetDimming() {
-        if (mStack != null) {
-            mStack.resetDimmingTag();
-            return;
-        }
-        mFirst.resetDimming();
-        mSecond.resetDimming();
-    }
-
-    boolean isDimming() {
-        if (mStack != null) {
-            return mStack.isDimming();
-        }
-        boolean result = mFirst.isDimming();
-        result |= mSecond.isDimming();
-        return result;
-    }
-
-    void stopDimmingIfNeeded() {
-        if (mStack != null) {
-            mStack.stopDimmingIfNeeded();
-            return;
-        }
-        mFirst.stopDimmingIfNeeded();
-        mSecond.stopDimmingIfNeeded();
-    }
-
-    void switchUserStacks(int userId) {
-        if (mStack != null) {
-            mStack.switchUser(userId);
-            return;
-        }
-        mFirst.switchUserStacks(userId);
-        mSecond.switchUserStacks(userId);
-    }
-
-    void close() {
-        if (mStack != null) {
-            mStack.mDimLayer.mDimSurface.destroy();
-            mStack.mAnimationBackgroundSurface.mDimSurface.destroy();
-            return;
-        }
-        mFirst.close();
-        mSecond.close();
-    }
-
-    public void dump(String prefix, PrintWriter pw) {
-        pw.print(prefix); pw.print("mParent="); pw.println(mParent);
-        pw.print(prefix); pw.print("mBounds="); pw.print(mBounds.toShortString());
-            pw.print(" mVertical="); pw.print(mVertical);
-            pw.print(" layoutNeeded="); pw.println(layoutNeeded);
-        if (mFirst != null) {
-            pw.print(prefix); pw.print("mFirst="); pw.println(System.identityHashCode(mFirst));
-            mFirst.dump(prefix + "  ", pw);
-            pw.print(prefix); pw.print("mSecond="); pw.println(System.identityHashCode(mSecond));
-            mSecond.dump(prefix + "  ", pw);
-        } else {
-            pw.print(prefix); pw.print("mStack="); pw.println(mStack);
-            mStack.dump(prefix + "  ", pw);
-        }
-    }
-
-    @Override
-    public String toString() {
-        if (mStack != null) {
-            return "Box{" + hashCode() + " stack=" + mStack.mStackId + "}";
-        }
-        return "Box{" + hashCode() + " parent=" + System.identityHashCode(mParent)
-                + " first=" + System.identityHashCode(mFirst)
-                + " second=" + System.identityHashCode(mSecond) + "}";
-    }
-}
diff --git a/services/java/com/android/server/wm/TaskStack.java b/services/java/com/android/server/wm/TaskStack.java
index cb29df4..df1d108 100644
--- a/services/java/com/android/server/wm/TaskStack.java
+++ b/services/java/com/android/server/wm/TaskStack.java
@@ -26,8 +26,6 @@
 import android.util.TypedValue;
 import com.android.server.EventLogTags;
 
-import static com.android.server.am.ActivityStackSupervisor.HOME_STACK_ID;
-
 import java.io.PrintWriter;
 import java.util.ArrayList;
 
@@ -49,8 +47,9 @@
      * mTaskHistory in the ActivityStack with the same mStackId */
     private final ArrayList<Task> mTasks = new ArrayList<Task>();
 
-    /** The StackBox this sits in. */
-    StackBox mStackBox;
+    /** Content limits relative to the DisplayContent this sits in. Empty indicates fullscreen,
+     * Nonempty is size of this TaskStack but is also used to scale if DisplayContent changes. */
+    Rect mBounds = new Rect();
 
     /** Used to support {@link android.view.WindowManager.LayoutParams#FLAG_DIM_BEHIND} */
     final DimLayer mDimLayer;
@@ -74,6 +73,9 @@
         mDisplayContent = displayContent;
         mDimLayer = new DimLayer(service, this);
         mAnimationBackgroundSurface = new DimLayer(service, this);
+        // TODO: remove bounds from log, they are always 0.
+        EventLog.writeEvent(EventLogTags.WM_STACK_CREATED, stackId, mBounds.left, mBounds.top,
+                mBounds.right, mBounds.bottom);
     }
 
     DisplayContent getDisplayContent() {
@@ -84,12 +86,64 @@
         return mTasks;
     }
 
-    boolean isHomeStack() {
-        return mStackId == HOME_STACK_ID;
+    private void resizeWindows() {
+        final boolean underStatusBar = mBounds.top == 0;
+
+        final ArrayList<WindowState> resizingWindows = mService.mResizingWindows;
+        for (int taskNdx = mTasks.size() - 1; taskNdx >= 0; --taskNdx) {
+            final ArrayList<AppWindowToken> activities = mTasks.get(taskNdx).mAppTokens;
+            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
+                final ArrayList<WindowState> windows = activities.get(activityNdx).allAppWindows;
+                for (int winNdx = windows.size() - 1; winNdx >= 0; --winNdx) {
+                    final WindowState win = windows.get(winNdx);
+                    if (!resizingWindows.contains(win)) {
+                        if (WindowManagerService.DEBUG_RESIZE) Slog.d(TAG,
+                                "setBounds: Resizing " + win);
+                        resizingWindows.add(win);
+                    }
+                    win.mUnderStatusBar = underStatusBar;
+                }
+            }
+        }
     }
 
-    boolean hasSibling() {
-        return mStackBox.mParent != null;
+    boolean setBounds(Rect bounds) {
+        if (mBounds.equals(bounds)) {
+            return false;
+        }
+
+        mDimLayer.setBounds(bounds);
+        mAnimationBackgroundSurface.setBounds(bounds);
+        mBounds.set(bounds);
+
+        resizeWindows();
+        return true;
+    }
+
+    void getBounds(Rect out) {
+        if (mBounds.isEmpty()) {
+            mDisplayContent.getLogicalDisplayRect(out);
+        } else {
+            out.set(mBounds);
+        }
+        out.intersect(mDisplayContent.mContentRect);
+    }
+
+    boolean isFullscreen() {
+        return mBounds.isEmpty();
+    }
+
+    void resizeBounds(float oldWidth, float oldHeight, float newWidth, float newHeight) {
+        if (oldWidth == newWidth && oldHeight == newHeight) {
+            return;
+        }
+        float widthScale = newWidth / oldWidth;
+        float heightScale = newHeight / oldHeight;
+        mBounds.left = (int)(mBounds.left * widthScale + 0.5);
+        mBounds.top = (int)(mBounds.top * heightScale + 0.5);
+        mBounds.right = (int)(mBounds.right * widthScale + 0.5);
+        mBounds.bottom = (int)(mBounds.bottom * heightScale + 0.5);
+        resizeWindows();
     }
 
     /**
@@ -97,9 +151,7 @@
      * @param task The task to add.
      * @param toTop Whether to add it to the top or bottom.
      */
-    boolean addTask(Task task, boolean toTop) {
-        mStackBox.makeDirty();
-
+    void addTask(Task task, boolean toTop) {
         int stackNdx;
         if (!toTop) {
             stackNdx = 0;
@@ -122,20 +174,20 @@
 
         task.mStack = this;
         mDisplayContent.addTask(task, toTop);
-        return mDisplayContent.moveHomeStackBox(mStackId == HOME_STACK_ID);
+        mDisplayContent.moveStack(this, true);
     }
 
-    boolean moveTaskToTop(Task task) {
+    void moveTaskToTop(Task task) {
         if (DEBUG_TASK_MOVEMENT) Slog.d(TAG, "moveTaskToTop: task=" + task + " Callers="
                 + Debug.getCallers(6));
         mTasks.remove(task);
-        return addTask(task, true);
+        addTask(task, true);
     }
 
-    boolean moveTaskToBottom(Task task) {
+    void moveTaskToBottom(Task task) {
         if (DEBUG_TASK_MOVEMENT) Slog.d(TAG, "moveTaskToBottom: task=" + task);
         mTasks.remove(task);
-        return addTask(task, false);
+        addTask(task, false);
     }
 
     /**
@@ -145,7 +197,6 @@
      */
     void removeTask(Task task) {
         if (DEBUG_TASK_MOVEMENT) Slog.d(TAG, "removeTask: task=" + task);
-        mStackBox.makeDirty();
         mTasks.remove(task);
         mDisplayContent.removeTask(task);
     }
@@ -154,7 +205,7 @@
         mAnimationBackgroundSurface.destroySurface();
         mDimLayer.destroySurface();
         EventLog.writeEvent(EventLogTags.WM_STACK_REMOVED, mStackId);
-        return mStackBox.remove();
+        return mDisplayContent.topStack().mStackId;
     }
 
     void resetAnimationBackgroundAnimator() {
@@ -259,28 +310,6 @@
         }
     }
 
-    void setBounds(Rect bounds, boolean underStatusBar) {
-        mDimLayer.setBounds(bounds);
-        mAnimationBackgroundSurface.setBounds(bounds);
-
-        final ArrayList<WindowState> resizingWindows = mService.mResizingWindows;
-        for (int taskNdx = mTasks.size() - 1; taskNdx >= 0; --taskNdx) {
-            final ArrayList<AppWindowToken> activities = mTasks.get(taskNdx).mAppTokens;
-            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
-                final ArrayList<WindowState> windows = activities.get(activityNdx).allAppWindows;
-                for (int winNdx = windows.size() - 1; winNdx >= 0; --winNdx) {
-                    final WindowState win = windows.get(winNdx);
-                    if (!resizingWindows.contains(win)) {
-                        if (WindowManagerService.DEBUG_RESIZE) Slog.d(TAG,
-                                "setBounds: Resizing " + win);
-                        resizingWindows.add(win);
-                    }
-                    win.mUnderStatusBar = underStatusBar;
-                }
-            }
-        }
-    }
-
     void switchUser(int userId) {
         int top = mTasks.size();
         for (int taskNdx = 0; taskNdx < top; ++taskNdx) {
@@ -293,6 +322,11 @@
         }
     }
 
+    void close() {
+        mDimLayer.mDimSurface.destroy();
+        mAnimationBackgroundSurface.mDimSurface.destroy();
+    }
+
     public void dump(String prefix, PrintWriter pw) {
         pw.print(prefix); pw.print("mStackId="); pw.println(mStackId);
         for (int taskNdx = 0; taskNdx < mTasks.size(); ++taskNdx) {
diff --git a/services/java/com/android/server/wm/WindowManagerService.java b/services/java/com/android/server/wm/WindowManagerService.java
index 28dde0d..060e89a 100644
--- a/services/java/com/android/server/wm/WindowManagerService.java
+++ b/services/java/com/android/server/wm/WindowManagerService.java
@@ -45,7 +45,6 @@
 import com.android.server.power.ShutdownThread;
 
 import android.Manifest;
-import android.app.ActivityManager.StackBoxInfo;
 import android.app.ActivityManagerNative;
 import android.app.IActivityManager;
 import android.app.StatusBarManager;
@@ -3775,10 +3774,8 @@
             if (stack == null) {
                 mFocusedStackFrame.setVisibility(false);
             } else {
-                final StackBox box = stack.mStackBox;
-                final Rect bounds = box.mBounds;
-                final boolean multipleStacks = box.mParent != null;
-                mFocusedStackFrame.setBounds(bounds);
+                mFocusedStackFrame.setBounds(stack);
+                final boolean multipleStacks = !stack.isFullscreen();
                 mFocusedStackFrame.setVisibility(multipleStacks);
             }
         } finally {
@@ -4783,10 +4780,12 @@
                 }
                 final TaskStack stack = task.mStack;
                 final DisplayContent displayContent = task.getDisplayContent();
-                final boolean isHomeStackTask = stack.isHomeStack();
-                if (isHomeStackTask != displayContent.homeOnTop()) {
-                    // First move the stack itself.
-                    displayContent.moveHomeStackBox(isHomeStackTask);
+                displayContent.moveStack(stack, true);
+                final TaskStack homeStack = displayContent.getHomeStack();
+                if (homeStack != stack) {
+                    // When a non-home stack moves to the top, the home stack moves to the
+                    // bottom.
+                    displayContent.moveStack(homeStack, false);
                 }
                 stack.moveTaskToTop(task);
             }
@@ -4817,36 +4816,19 @@
     /**
      * Create a new TaskStack and place it next to an existing stack.
      * @param stackId The unique identifier of the new stack.
-     * @param relativeStackBoxId The existing stack that this stack goes before or after.
-     * @param position One of:
-     *      {@link StackBox#TASK_STACK_GOES_BEFORE}
-     *      {@link StackBox#TASK_STACK_GOES_AFTER}
-     *      {@link StackBox#TASK_STACK_GOES_ABOVE}
-     *      {@link StackBox#TASK_STACK_GOES_BELOW}
-     *      {@link StackBox#TASK_STACK_GOES_UNDER}
-     *      {@link StackBox#TASK_STACK_GOES_OVER}
-     * @param weight Relative weight for determining how big to make the new TaskStack.
      */
-    public void createStack(int stackId, int relativeStackBoxId, int position, float weight) {
+    public void createStack(int stackId, int displayId) {
         synchronized (mWindowMap) {
-            if (position <= StackBox.TASK_STACK_GOES_BELOW &&
-                    (weight < STACK_WEIGHT_MIN || weight > STACK_WEIGHT_MAX)) {
-                throw new IllegalArgumentException(
-                        "createStack: weight must be between " + STACK_WEIGHT_MIN + " and " +
-                        STACK_WEIGHT_MAX + ", weight=" + weight);
-            }
             final int numDisplays = mDisplayContents.size();
             for (int displayNdx = 0; displayNdx < numDisplays; ++displayNdx) {
                 final DisplayContent displayContent = mDisplayContents.valueAt(displayNdx);
-                TaskStack stack = displayContent.createStack(stackId, relativeStackBoxId, position,
-                        weight);
-                if (stack != null) {
+                if (displayContent.getDisplayId() == displayId) {
+                    TaskStack stack = displayContent.createStack(stackId);
                     mStackIdToStack.put(stackId, stack);
                     performLayoutAndPlaceSurfacesLocked();
                     return;
                 }
             }
-            Slog.e(TAG, "createStack: Unable to find relativeStackBoxId=" + relativeStackBoxId);
         }
     }
 
@@ -4893,40 +4875,27 @@
         }
     }
 
-    public void resizeStackBox(int stackBoxId, float weight) {
-        if (weight < STACK_WEIGHT_MIN || weight > STACK_WEIGHT_MAX) {
-            throw new IllegalArgumentException(
-                    "resizeStack: weight must be between " + STACK_WEIGHT_MIN + " and " +
-                    STACK_WEIGHT_MAX + ", weight=" + weight);
-        }
+    public void resizeStack(int stackId, Rect bounds) {
         synchronized (mWindowMap) {
-            final int numDisplays = mDisplayContents.size();
-            for (int displayNdx = 0; displayNdx < numDisplays; ++displayNdx) {
-                if (mDisplayContents.valueAt(displayNdx).resizeStack(stackBoxId, weight)) {
-                    performLayoutAndPlaceSurfacesLocked();
-                    return;
-                }
+            final TaskStack stack = mStackIdToStack.get(stackId);
+            if (stack == null) {
+                throw new IllegalArgumentException("resizeStack: stackId " + stackId
+                        + " not found.");
             }
-        }
-        throw new IllegalArgumentException("resizeStack: stackBoxId " + stackBoxId
-                + " not found.");
-    }
-
-    public ArrayList<StackBoxInfo> getStackBoxInfos() {
-        synchronized(mWindowMap) {
-            return getDefaultDisplayContentLocked().getStackBoxInfos();
+            if (stack.setBounds(bounds)) {
+                stack.getDisplayContent().layoutNeeded = true;
+                performLayoutAndPlaceSurfacesLocked();
+            }
         }
     }
 
-    public Rect getStackBounds(int stackId) {
-        final int numDisplays = mDisplayContents.size();
-        for (int displayNdx = 0; displayNdx < numDisplays; ++displayNdx) {
-            Rect bounds = mDisplayContents.valueAt(displayNdx).getStackBounds(stackId);
-            if (bounds != null) {
-                return bounds;
-            }
+    public void getStackBounds(int stackId, Rect bounds) {
+        final TaskStack stack = mStackIdToStack.get(stackId);
+        if (stack != null) {
+            stack.getBounds(bounds);
+            return;
         }
-        return null;
+        bounds.setEmpty();
     }
 
     // -------------------------------------------------------------
@@ -5583,7 +5552,7 @@
                                 continue;
                             }
                             appWin = ws;
-                            stackBounds.set(ws.getStackBounds());
+                            ws.getStackBounds(stackBounds);
                         }
                     }
 
@@ -8210,7 +8179,7 @@
         }
 
         mPolicy.getContentRectLw(mTmpContentRect);
-        displayContent.setStackBoxSize(mTmpContentRect);
+        displayContent.resize(mTmpContentRect);
 
         int seq = mLayoutSeq+1;
         if (seq < 0) seq = 0;
diff --git a/services/java/com/android/server/wm/WindowState.java b/services/java/com/android/server/wm/WindowState.java
index 4d53cea..e6c1e98 100644
--- a/services/java/com/android/server/wm/WindowState.java
+++ b/services/java/com/android/server/wm/WindowState.java
@@ -463,8 +463,8 @@
         mHaveFrame = true;
 
         TaskStack stack = mAppToken != null ? getStack() : null;
-        if (stack != null && stack.hasSibling()) {
-            mContainingFrame.set(getStackBounds(stack));
+        if (stack != null && !stack.isFullscreen()) {
+            getStackBounds(stack, mContainingFrame);
             if (mUnderStatusBar) {
                 mContainingFrame.top = pf.top;
             }
@@ -723,15 +723,16 @@
         return mDisplayContent.getHomeStack();
     }
 
-    Rect getStackBounds() {
-        return getStackBounds(getStack());
+    void getStackBounds(Rect bounds) {
+        getStackBounds(getStack(), bounds);
     }
 
-    private Rect getStackBounds(TaskStack stack) {
+    private void getStackBounds(TaskStack stack, Rect bounds) {
         if (stack != null) {
-            return stack.mStackBox.mBounds;
+            stack.getBounds(bounds);
+            return;
         }
-        return mFrame;
+        bounds.set(mFrame);
     }
 
     public long getInputDispatchingTimeoutNanos() {