Merge "Only allow activities to move to full screen stack."
diff --git a/core/java/android/app/Activity.java b/core/java/android/app/Activity.java
index 8346161..64642ac 100644
--- a/core/java/android/app/Activity.java
+++ b/core/java/android/app/Activity.java
@@ -62,7 +62,6 @@
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.drawable.Drawable;
-import android.graphics.Rect;
 import android.media.AudioManager;
 import android.media.session.MediaController;
 import android.net.Uri;
@@ -2807,17 +2806,15 @@
 
 
     /**
-     * Called to move the window and its activity/task to a different stack container.
-     * For example, a window can move between
-     * {@link android.app.ActivityManager.StackId#FULLSCREEN_WORKSPACE_STACK_ID} stack and
-     * {@link android.app.ActivityManager.StackId#FREEFORM_WORKSPACE_STACK_ID} stack.
+     * Moves the activity from
+     * {@link android.app.ActivityManager.StackId#FREEFORM_WORKSPACE_STACK_ID} to
+     * {@link android.app.ActivityManager.StackId#FULLSCREEN_WORKSPACE_STACK_ID} stack.
      *
-     * @param stackId stack Id to change to.
      * @hide
      */
     @Override
-    public void changeWindowStack(int stackId) throws RemoteException {
-        ActivityManagerNative.getDefault().moveActivityToStack(mToken, stackId);
+    public void exitFreeformMode() throws RemoteException {
+        ActivityManagerNative.getDefault().exitFreeformMode(mToken);
     }
 
     /** Returns the current stack Id for the window.
diff --git a/core/java/android/app/ActivityManagerNative.java b/core/java/android/app/ActivityManagerNative.java
index da21099..4bea112 100644
--- a/core/java/android/app/ActivityManagerNative.java
+++ b/core/java/android/app/ActivityManagerNative.java
@@ -2752,11 +2752,10 @@
             reply.writeInt(stackId);
             return true;
         }
-        case MOVE_ACTIVITY_TO_STACK_TRANSACTION: {
+        case EXIT_FREEFORM_MODE_TRANSACTION: {
             data.enforceInterface(IActivityManager.descriptor);
             IBinder token = data.readStrongBinder();
-            int stackId = data.readInt();
-            moveActivityToStack(token, stackId);
+            exitFreeformMode(token);
             reply.writeNoException();
             return true;
         }
@@ -6457,13 +6456,12 @@
     }
 
     @Override
-    public void moveActivityToStack(IBinder token, int stackId) throws RemoteException {
+    public void exitFreeformMode(IBinder token) throws RemoteException {
         Parcel data = Parcel.obtain();
         Parcel reply = Parcel.obtain();
         data.writeInterfaceToken(IActivityManager.descriptor);
         data.writeStrongBinder(token);
-        data.writeInt(stackId);
-        mRemote.transact(MOVE_ACTIVITY_TO_STACK_TRANSACTION, data, reply, 0);
+        mRemote.transact(EXIT_FREEFORM_MODE_TRANSACTION, data, reply, 0);
         reply.readException();
         data.recycle();
         reply.recycle();
diff --git a/core/java/android/app/IActivityManager.java b/core/java/android/app/IActivityManager.java
index ceb14ad..8804c8b 100644
--- a/core/java/android/app/IActivityManager.java
+++ b/core/java/android/app/IActivityManager.java
@@ -564,7 +564,7 @@
     public boolean stopBinderTrackingAndDump(ParcelFileDescriptor fd) throws RemoteException;
 
     public int getActivityStackId(IBinder token) throws RemoteException;
-    public void moveActivityToStack(IBinder token, int stackId) throws RemoteException;
+    public void exitFreeformMode(IBinder token) throws RemoteException;
 
     public void suppressResizeConfigChanges(boolean suppress) throws RemoteException;
 
@@ -933,7 +933,7 @@
     int STOP_BINDER_TRACKING_AND_DUMP_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION + 341;
     int POSITION_TASK_IN_STACK_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION + 342;
     int GET_ACTIVITY_STACK_ID_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION + 343;
-    int MOVE_ACTIVITY_TO_STACK_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION + 344;
+    int EXIT_FREEFORM_MODE_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION + 344;
     int REPORT_SIZE_CONFIGURATIONS = IBinder.FIRST_CALL_TRANSACTION + 345;
     int MOVE_TASK_TO_DOCKED_STACK_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION + 346;
     int SUPPRESS_RESIZE_CONFIG_CHANGES_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION + 347;
diff --git a/core/java/android/view/Window.java b/core/java/android/view/Window.java
index d7a98ab..0b06d15 100644
--- a/core/java/android/view/Window.java
+++ b/core/java/android/view/Window.java
@@ -571,14 +571,11 @@
     /** @hide */
     public interface WindowControllerCallback {
         /**
-         * Called to move the window and its activity/task to a different stack container.
-         * For example, a window can move between
-         * {@link android.app.ActivityManager.StackId#FULLSCREEN_WORKSPACE_STACK_ID} stack and
-         * {@link android.app.ActivityManager.StackId#FREEFORM_WORKSPACE_STACK_ID} stack.
-         *
-         * @param stackId stack Id to change to.
+         * Moves the activity from
+         * {@link android.app.ActivityManager.StackId#FREEFORM_WORKSPACE_STACK_ID} to
+         * {@link android.app.ActivityManager.StackId#FULLSCREEN_WORKSPACE_STACK_ID} stack.
          */
-        void changeWindowStack(int stackId) throws RemoteException;
+        void exitFreeformMode() throws RemoteException;
 
         /** Returns the current stack Id for the window. */
         int getWindowStackId() throws RemoteException;
diff --git a/core/java/com/android/internal/widget/DecorCaptionView.java b/core/java/com/android/internal/widget/DecorCaptionView.java
index c3fe9e7..409a17f 100644
--- a/core/java/com/android/internal/widget/DecorCaptionView.java
+++ b/core/java/com/android/internal/widget/DecorCaptionView.java
@@ -16,8 +16,6 @@
 
 package com.android.internal.widget;
 
-import static android.app.ActivityManager.StackId.FULLSCREEN_WORKSPACE_STACK_ID;
-
 import android.content.Context;
 import android.graphics.Color;
 import android.graphics.Rect;
@@ -351,7 +349,7 @@
         Window.WindowControllerCallback callback = mOwner.getWindowControllerCallback();
         if (callback != null) {
             try {
-                callback.changeWindowStack(FULLSCREEN_WORKSPACE_STACK_ID);
+                callback.exitFreeformMode();
             } catch (RemoteException ex) {
                 Log.e(TAG, "Cannot change task workspace.");
             }
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 461191c..bac2295 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -9462,23 +9462,23 @@
     }
 
     @Override
-    public void moveActivityToStack(IBinder token, int stackId) throws RemoteException {
-        if (stackId == HOME_STACK_ID) {
-            throw new IllegalArgumentException(
-                    "moveActivityToStack: Attempt to move token " + token + " to home stack");
-        }
+    public void exitFreeformMode(IBinder token) throws RemoteException {
         synchronized (this) {
             long ident = Binder.clearCallingIdentity();
             try {
                 final ActivityRecord r = ActivityRecord.forTokenLocked(token);
                 if (r == null) {
                     throw new IllegalArgumentException(
-                            "moveActivityToStack: No activity record matching token=" + token);
+                            "exitFreeformMode: No activity record matching token=" + token);
                 }
-                if (DEBUG_STACK) Slog.d(TAG_STACK, "moveActivityToStack: moving r=" + r
-                        + " to stackId=" + stackId);
-                mStackSupervisor.moveTaskToStackLocked(r.task.taskId, stackId, ON_TOP, !FORCE_FOCUS,
-                        "moveActivityToStack", ANIMATE);
+                final ActivityStack stack = r.getStackLocked(token);
+                if (stack == null || stack.mStackId != FREEFORM_WORKSPACE_STACK_ID) {
+                    throw new IllegalStateException(
+                            "exitFreeformMode: You can only go fullscreen from freeform.");
+                }
+                if (DEBUG_STACK) Slog.d(TAG_STACK, "exitFreeformMode: " + r);
+                mStackSupervisor.moveTaskToStackLocked(r.task.taskId, FULLSCREEN_WORKSPACE_STACK_ID,
+                        ON_TOP, !FORCE_FOCUS, "exitFreeformMode", ANIMATE);
             } finally {
                 Binder.restoreCallingIdentity(ident);
             }