Support launching home activity on secondary display

- Add a new flag indicating that the display should show
  system decorations, such as status bar, nav bar, home and IME.
- Automatically launches home activity on secondary display
  if the display support system decorations and home
  activity has multiple instances supports.
- Remove ActivityStackSupervisor#mHomeStack and move several
  home stack related methods to ActivityDisplay.

Bug: 111363427
Test: atest ActivityManagerMultiDisplayTests
      atest com.android.server.am
      Manual test on virtual display and chromecast

Change-Id: I48fe245ad12965a19a6768f5dbb4e974ce94b01a
diff --git a/core/java/android/hardware/display/DisplayManager.java b/core/java/android/hardware/display/DisplayManager.java
index e8fb287..09113e5 100644
--- a/core/java/android/hardware/display/DisplayManager.java
+++ b/core/java/android/hardware/display/DisplayManager.java
@@ -297,6 +297,15 @@
      */
     public static final int VIRTUAL_DISPLAY_FLAG_DESTROY_CONTENT_ON_REMOVAL = 1 << 8;
 
+    /**
+     * Virtual display flag: Indicates that the display should support system decorations. Virtual
+     * displays without this flag shouldn't show home, IME or any other system decorations.
+     *
+     * @see #createVirtualDisplay
+     * @hide
+     */
+    public static final int VIRTUAL_DISPLAY_FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS = 1 << 9;
+
     /** @hide */
     public DisplayManager(Context context) {
         mContext = context;
diff --git a/core/java/android/view/Display.java b/core/java/android/view/Display.java
index 4d96fc3..719a401 100644
--- a/core/java/android/view/Display.java
+++ b/core/java/android/view/Display.java
@@ -221,6 +221,18 @@
     public static final int FLAG_CAN_SHOW_WITH_INSECURE_KEYGUARD = 1 << 5;
 
     /**
+     * Display flag: Indicates that the display should show system decorations.
+     * <p>
+     * This flag identifies secondary displays that should show system decorations, such as status
+     * bar, navigation bar, home activity or IME.
+     * </p>
+     *
+     * @see #supportsSystemDecorations
+     * @hide
+     */
+    public static final int FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS = 1 << 6;
+
+    /**
      * Display flag: Indicates that the contents of the display should not be scaled
      * to fit the physical screen dimensions.  Used for development only to emulate
      * devices with smaller physicals screens while preserving density.
@@ -874,6 +886,16 @@
     }
 
     /**
+     * Returns whether this display should support showing system decorations.
+     *
+     * @see #FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS
+     * @hide
+     */
+    public boolean supportsSystemDecorations() {
+        return (mDisplayInfo.flags & FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS) != 0;
+    }
+
+    /**
      * Returns the display's HDR capabilities.
      *
      * @see #isHdr()
diff --git a/services/core/java/com/android/server/am/ActivityDisplay.java b/services/core/java/com/android/server/am/ActivityDisplay.java
index fab967c..6012823 100644
--- a/services/core/java/com/android/server/am/ActivityDisplay.java
+++ b/services/core/java/com/android/server/am/ActivityDisplay.java
@@ -51,6 +51,7 @@
 import android.app.ActivityOptions;
 import android.app.WindowConfiguration;
 import android.graphics.Point;
+import android.os.UserHandle;
 import android.util.IntArray;
 import android.util.Slog;
 import android.util.proto.ProtoOutputStream;
@@ -911,6 +912,13 @@
         return mDisplayAccessUIDs;
     }
 
+    /**
+     * @see Display#FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS
+     */
+    boolean supportsSystemDecorations() {
+        return mDisplay.supportsSystemDecorations();
+    }
+
     private boolean shouldDestroyContentOnRemove() {
         return mDisplay.getRemoveMode() == REMOVE_MODE_DESTROY_CONTENT;
     }
@@ -981,6 +989,57 @@
         positionChildAt(stack, Math.max(0, insertIndex));
     }
 
+    void moveHomeStackToFront(String reason) {
+        if (mHomeStack != null) {
+            mHomeStack.moveToFront(reason);
+        }
+    }
+
+    /** Returns true if the focus activity was adjusted to the home stack top activity. */
+    boolean moveHomeActivityToTop(String reason) {
+        final ActivityRecord top = getHomeActivity();
+        if (top == null) {
+            return false;
+        }
+        mSupervisor.moveFocusableActivityToTop(top, reason);
+        return true;
+    }
+
+    @Nullable
+    ActivityStack getHomeStack() {
+        return mHomeStack;
+    }
+
+    @Nullable
+    ActivityRecord getHomeActivity() {
+        return getHomeActivityForUser(mSupervisor.mCurrentUser);
+    }
+
+    @Nullable
+    ActivityRecord getHomeActivityForUser(int userId) {
+        if (mHomeStack == null) {
+            return null;
+        }
+
+        final ArrayList<TaskRecord> tasks = mHomeStack.getAllTasks();
+        for (int taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) {
+            final TaskRecord task = tasks.get(taskNdx);
+            if (!task.isActivityTypeHome()) {
+                continue;
+            }
+
+            final ArrayList<ActivityRecord> activities = task.mActivities;
+            for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
+                final ActivityRecord r = activities.get(activityNdx);
+                if (r.isActivityTypeHome()
+                        && ((userId == UserHandle.USER_ALL) || (r.userId == userId))) {
+                    return r;
+                }
+            }
+        }
+        return null;
+    }
+
     boolean isSleeping() {
         return mSleeping;
     }
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index aa14da0..6ffa4c0 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -90,6 +90,7 @@
 import static android.provider.Settings.Global.NETWORK_ACCESS_TIMEOUT_MS;
 import static android.provider.Settings.Global.WAIT_FOR_DEBUGGER;
 import static android.text.format.DateUtils.DAY_IN_MILLIS;
+import static android.view.Display.DEFAULT_DISPLAY;
 
 import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_ALL;
 import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_ANR;
@@ -3725,6 +3726,14 @@
     }
 
     boolean startHomeActivityLocked(int userId, String reason) {
+        return startHomeActivityLocked(userId, reason, DEFAULT_DISPLAY);
+    }
+
+    /**
+     * This starts home activity on displays that can have system decorations and only if the
+     * home activity can have multiple instances.
+     */
+    boolean startHomeActivityLocked(int userId, String reason, int displayId) {
         if (mFactoryTest == FactoryTest.FACTORY_TEST_LOW_LEVEL
                 && mTopAction == null) {
             // We are running in factory test mode, but unable to find
@@ -3748,7 +3757,8 @@
                 // For ANR debugging to verify if the user activity is the one that actually
                 // launched.
                 final String myReason = reason + ":" + userId + ":" + resolvedUserId;
-                mActivityTaskManager.getActivityStartController().startHomeActivity(intent, aInfo, myReason);
+                mActivityTaskManager.getActivityStartController().startHomeActivity(intent, aInfo,
+                        myReason, displayId);
             }
         } else {
             Slog.wtf(TAG, "No home screen found for " + intent, new Throwable());
@@ -8817,7 +8827,7 @@
                         ? new ActivityOptions(options)
                         : ActivityOptions.makeBasic();
                 activityOptions.setLaunchTaskId(
-                        mStackSupervisor.getHomeActivity().getTask().taskId);
+                        mStackSupervisor.getDefaultDisplayHomeActivity().getTask().taskId);
                 mContext.startActivityAsUser(intent, activityOptions.toBundle(),
                         UserHandle.CURRENT);
             } finally {
diff --git a/services/core/java/com/android/server/am/ActivityStack.java b/services/core/java/com/android/server/am/ActivityStack.java
index 29b04cc..2ab9388 100644
--- a/services/core/java/com/android/server/am/ActivityStack.java
+++ b/services/core/java/com/android/server/am/ActivityStack.java
@@ -1102,8 +1102,7 @@
         if (!isActivityTypeHome() && returnsToHomeStack()) {
             // Make sure the home stack is behind this stack since that is where we should return to
             // when this stack is no longer visible.
-            // TODO(b/111541062): Move home stack on the current display
-            mStackSupervisor.moveHomeStackToFront(reason + " returnToHome");
+            display.moveHomeStackToFront(reason + " returnToHome");
         }
 
         display.positionChildAtTop(this, true /* includingParents */);
@@ -2854,9 +2853,7 @@
         if (DEBUG_STATES) Slog.d(TAG_STATES,
                 "resumeTopActivityInNextFocusableStack: " + reason + ", go home");
         if (DEBUG_STACK) mStackSupervisor.validateTopActivitiesLocked();
-        // Only resume home if on home display
-        return isOnHomeDisplay() &&
-                mStackSupervisor.resumeHomeStackTask(prev, reason);
+        return mStackSupervisor.resumeHomeActivity(prev, reason, mDisplayId);
     }
 
     /** Returns the position the input task should be placed in this stack. */
@@ -3450,8 +3447,8 @@
         final String myReason = reason + " adjustFocus";
 
         if (next == r) {
-            mStackSupervisor.moveFocusableActivityStackToFrontLocked(
-                    mStackSupervisor.topRunningActivityLocked(), myReason);
+            mStackSupervisor.moveFocusableActivityToTop(mStackSupervisor.topRunningActivityLocked(),
+                    myReason);
             return;
         }
 
@@ -3482,7 +3479,7 @@
         }
 
         // Whatever...go home.
-        mStackSupervisor.moveHomeStackTaskToTop(myReason);
+        getDisplay().moveHomeActivityToTop(myReason);
     }
 
     /**
@@ -3511,7 +3508,7 @@
         if (stack.isActivityTypeHome() && (top == null || !top.visible)) {
             // If we will be focusing on the home stack next and its current top activity isn't
             // visible, then use the move the home stack task to top to make the activity visible.
-            mStackSupervisor.moveHomeStackTaskToTop(reason);
+            stack.getDisplay().moveHomeActivityToTop(reason);
             return stack;
         }
 
@@ -4619,22 +4616,6 @@
         mStackSupervisor.invalidateTaskLayers();
     }
 
-    void moveHomeStackTaskToTop() {
-        if (!isActivityTypeHome()) {
-            throw new IllegalStateException("Calling moveHomeStackTaskToTop() on non-home stack: "
-                    + this);
-        }
-        final int top = mTaskHistory.size() - 1;
-        if (top >= 0) {
-            final TaskRecord task = mTaskHistory.get(top);
-            if (DEBUG_TASKS || DEBUG_STACK) Slog.d(TAG_STACK,
-                    "moveHomeStackTaskToTop: moving " + task);
-            mTaskHistory.remove(top);
-            mTaskHistory.add(top, task);
-            updateTaskMovement(task, true);
-        }
-    }
-
     final void moveTaskToFrontLocked(TaskRecord tr, boolean noAnimation, ActivityOptions options,
             AppTimeTracker timeTracker, String reason) {
         if (DEBUG_SWITCH) Slog.v(TAG_SWITCH, "moveTaskToFront: " + tr);
@@ -4682,7 +4663,7 @@
 
             // Set focus to the top running activity of this stack.
             final ActivityRecord r = topRunningActivityLocked();
-            mStackSupervisor.moveFocusableActivityStackToFrontLocked(r, reason);
+            mStackSupervisor.moveFocusableActivityToTop(r, reason);
 
             if (DEBUG_TRANSITION) Slog.v(TAG_TRANSITION, "Prepare to front transition: task=" + tr);
             if (noAnimation) {
@@ -5223,11 +5204,11 @@
             if (DEBUG_STACK) Slog.i(TAG_STACK, "removeTask: removing stack=" + this);
             // We only need to adjust focused stack if this stack is in focus and we are not in the
             // process of moving the task to the top of the stack that will be focused.
-            if (isOnHomeDisplay() && mode != REMOVE_TASK_MODE_MOVING_TO_TOP
+            if (mode != REMOVE_TASK_MODE_MOVING_TO_TOP
                     && mStackSupervisor.isTopDisplayFocusedStack(this)) {
                 String myReason = reason + " leftTaskHistoryEmpty";
                 if (!inMultiWindowMode() || adjustFocusToNextFocusableStack(myReason) == null) {
-                    mStackSupervisor.moveHomeStackToFront(myReason);
+                    getDisplay().moveHomeStackToFront(myReason);
                 }
             }
             if (isAttached()) {
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index 8ff55f6..7f1e149 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -40,6 +40,8 @@
 import static android.app.WindowConfiguration.WINDOWING_MODE_UNDEFINED;
 import static android.app.WindowConfiguration.activityTypeToString;
 import static android.app.WindowConfiguration.windowingModeToString;
+import static android.content.pm.ActivityInfo.LAUNCH_SINGLE_INSTANCE;
+import static android.content.pm.ActivityInfo.LAUNCH_SINGLE_TASK;
 import static android.content.pm.PackageManager.PERMISSION_DENIED;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.graphics.Rect.copyOrNull;
@@ -335,10 +337,6 @@
     /** The current user */
     int mCurrentUser;
 
-    /** The stack containing the launcher app. Assumed to always be attached to
-     * Display.DEFAULT_DISPLAY. */
-    ActivityStack mHomeStack;
-
     /** If this is the same as mFocusedStack then the activity on the top of the focused stack has
      * been resumed. If stacks are changing position this will hold the old stack until the new
      * stack becomes resumed after which it will be set to mFocusedStack. */
@@ -693,7 +691,8 @@
         calculateDefaultMinimalSizeOfResizeableTasks();
 
         final ActivityDisplay defaultDisplay = getDefaultDisplay();
-        mHomeStack = mLastFocusedStack = defaultDisplay.getOrCreateStack(
+
+        mLastFocusedStack = defaultDisplay.getOrCreateStack(
                 WINDOWING_MODE_FULLSCREEN, ACTIVITY_TYPE_HOME, ON_TOP);
         positionChildAt(defaultDisplay, ActivityDisplay.POSITION_TOP);
     }
@@ -782,7 +781,7 @@
             if (focusCandidate == null) {
                 Slog.w(TAG,
                         "setFocusStackUnchecked: No focusable stack found, focus home as default");
-                focusCandidate = mHomeStack;
+                focusCandidate = getDefaultDisplay().getHomeStack();
             }
         }
 
@@ -803,10 +802,6 @@
         }
     }
 
-    void moveHomeStackToFront(String reason) {
-        mHomeStack.moveToFront(reason);
-    }
-
     void moveRecentsStackToFront(String reason) {
         final ActivityStack recentsStack = getDefaultDisplay().getStack(
                 WINDOWING_MODE_UNDEFINED, ACTIVITY_TYPE_RECENTS);
@@ -815,34 +810,47 @@
         }
     }
 
-    /** Returns true if the focus activity was adjusted to the home stack top activity. */
-    boolean moveHomeStackTaskToTop(String reason) {
-        mHomeStack.moveHomeStackTaskToTop();
-
-        final ActivityRecord top = getHomeActivity();
-        if (top == null) {
-            return false;
-        }
-        moveFocusableActivityStackToFrontLocked(top, reason);
-        return true;
-    }
-
-    boolean resumeHomeStackTask(ActivityRecord prev, String reason) {
+    boolean resumeHomeActivity(ActivityRecord prev, String reason, int displayId) {
         if (!mService.isBooting() && !mService.isBooted()) {
             // Not ready yet!
             return false;
         }
 
-        mHomeStack.moveHomeStackTaskToTop();
-        ActivityRecord r = getHomeActivity();
-        final String myReason = reason + " resumeHomeStackTask";
+        if (displayId == INVALID_DISPLAY) {
+            displayId = DEFAULT_DISPLAY;
+        }
+
+        final ActivityRecord r = getActivityDisplay(displayId).getHomeActivity();
+        final String myReason = reason + " resumeHomeActivity";
 
         // Only resume home activity if isn't finishing.
         if (r != null && !r.finishing) {
-            moveFocusableActivityStackToFrontLocked(r, myReason);
-            return resumeFocusedStacksTopActivitiesLocked(mHomeStack, prev, null);
+            moveFocusableActivityToTop(r, myReason);
+            return resumeFocusedStacksTopActivitiesLocked(r.getStack(), prev, null);
         }
-        return mService.mAm.startHomeActivityLocked(mCurrentUser, myReason);
+        return mService.mAm.startHomeActivityLocked(mCurrentUser, myReason, displayId);
+    }
+
+    boolean canStartHomeOnDisplay(ActivityInfo homeActivity, int displayId) {
+        if (displayId == DEFAULT_DISPLAY) {
+            // No restrictions to default display.
+            return true;
+        }
+
+        final ActivityDisplay display = getActivityDisplay(displayId);
+        if (display == null || display.isRemoved() || !display.supportsSystemDecorations()) {
+            // Can't launch home on display that doesn't support system decorations.
+            return false;
+        }
+
+        final boolean supportMultipleInstance = homeActivity.launchMode != LAUNCH_SINGLE_TASK
+                && homeActivity.launchMode != LAUNCH_SINGLE_INSTANCE;
+        if (!supportMultipleInstance) {
+            // Can't launch home on other displays if it requested to be single instance.
+            return false;
+        }
+
+        return true;
     }
 
     TaskRecord anyTaskForIdLocked(int id) {
@@ -2206,7 +2214,8 @@
      */
     void updateUserStackLocked(int userId, ActivityStack stack) {
         if (userId != mCurrentUser) {
-            mUserStackInFront.put(userId, stack != null ? stack.getStackId() : mHomeStack.mStackId);
+            mUserStackInFront.put(userId, stack != null ? stack.getStackId()
+                    : getDefaultDisplay().getHomeStack().mStackId);
         }
     }
 
@@ -2348,7 +2357,7 @@
      */
     void findTaskToMoveToFront(TaskRecord task, int flags, ActivityOptions options, String reason,
             boolean forceNonResizeable) {
-        final ActivityStack currentStack = task.getStack();
+        ActivityStack currentStack = task.getStack();
         if (currentStack == null) {
             Slog.e(TAG, "findTaskToMoveToFront: can't move task="
                     + task + " to front. Stack is null");
@@ -2359,13 +2368,15 @@
             mUserLeaving = true;
         }
 
+        // TODO(b/111363427): The moving-to-top task may not be on the top display, so it could be
+        // different from where the prev activity stays on.
         final ActivityRecord prev = topRunningActivityLocked();
 
         if ((flags & ActivityManager.MOVE_TASK_WITH_HOME) != 0
                 || (prev != null && prev.isActivityTypeRecents())) {
             // Caller wants the home activity moved with it or the previous task is recents in which
             // case we always return home from the task we are moving to the front.
-            moveHomeStackToFront("findTaskToMoveToFront");
+            currentStack.getDisplay().moveHomeStackToFront("findTaskToMoveToFront");
         }
 
         if (task.isResizeable() && canUseActivityOptionsLaunchBounds(options)) {
@@ -2377,7 +2388,7 @@
             if (stack != currentStack) {
                 task.reparent(stack, ON_TOP, REPARENT_KEEP_STACK_AT_FRONT, !ANIMATE, DEFER_RESUME,
                         "findTaskToMoveToFront");
-                stack = currentStack;
+                currentStack = stack;
                 // moveTaskToStackUncheckedLocked() should already placed the task on top,
                 // still need moveTaskToFrontLocked() below for any transition settings.
             }
@@ -2644,6 +2655,12 @@
         if (preferredFocusableStack != null) {
             return preferredFocusableStack;
         }
+        if (preferredDisplay.supportsSystemDecorations()) {
+            // Stop looking for focusable stack on other displays because the preferred display
+            // supports system decorations. Home activity would be launched on the same display if
+            // no focusable stack found.
+            return null;
+        }
 
         // Now look through all displays
         for (int i = mActivityDisplays.size() - 1; i >= 0; --i) {
@@ -2687,25 +2704,12 @@
         return null;
     }
 
-    ActivityRecord getHomeActivity() {
-        return getHomeActivityForUser(mCurrentUser);
+    ActivityRecord getDefaultDisplayHomeActivity() {
+        return getDefaultDisplayHomeActivityForUser(mCurrentUser);
     }
 
-    ActivityRecord getHomeActivityForUser(int userId) {
-        final ArrayList<TaskRecord> tasks = mHomeStack.getAllTasks();
-        for (int taskNdx = tasks.size() - 1; taskNdx >= 0; --taskNdx) {
-            final TaskRecord task = tasks.get(taskNdx);
-            if (task.isActivityTypeHome()) {
-                final ArrayList<ActivityRecord> activities = task.mActivities;
-                for (int activityNdx = activities.size() - 1; activityNdx >= 0; --activityNdx) {
-                    final ActivityRecord r = activities.get(activityNdx);
-                    if (r.isActivityTypeHome()
-                            && ((userId == UserHandle.USER_ALL) || (r.userId == userId))) {
-                        return r;
-                    }
-                }
-            }
-        }
+    ActivityRecord getDefaultDisplayHomeActivityForUser(int userId) {
+        getActivityDisplay(DEFAULT_DISPLAY).getHomeActivityForUser(userId);
         return null;
     }
 
@@ -3419,7 +3423,8 @@
     }
 
     /** Move activity with its stack to front and make the stack focused. */
-    boolean moveFocusableActivityStackToFrontLocked(ActivityRecord r, String reason) {
+    // TODO(b/111363427): Move this method to ActivityRecord.
+    boolean moveFocusableActivityToTop(ActivityRecord r, String reason) {
         if (r == null || !r.isFocusable()) {
             if (DEBUG_FOCUS) Slog.d(TAG_FOCUS,
                     "moveActivityStackToFront: unfocusable r=" + r);
@@ -3828,7 +3833,8 @@
         removeStacksInWindowingModes(WINDOWING_MODE_PINNED);
 
         mUserStackInFront.put(mCurrentUser, focusStackId);
-        final int restoreStackId = mUserStackInFront.get(userId, mHomeStack.mStackId);
+        final int restoreStackId =
+                mUserStackInFront.get(userId, getDefaultDisplay().getHomeStack().mStackId);
         mCurrentUser = userId;
 
         mStartingUsers.add(uss);
@@ -3846,14 +3852,14 @@
 
         ActivityStack stack = getStack(restoreStackId);
         if (stack == null) {
-            stack = mHomeStack;
+            stack = getDefaultDisplay().getHomeStack();
         }
         final boolean homeInFront = stack.isActivityTypeHome();
         if (stack.isOnHomeDisplay()) {
             stack.moveToFront("switchUserOnHomeDisplay");
         } else {
             // Stack was moved to another display while user was swapped out.
-            resumeHomeStackTask(null, "switchUserOnOtherDisplay");
+            resumeHomeActivity(null, "switchUserOnOtherDisplay", DEFAULT_DISPLAY);
         }
         return homeInFront;
     }
@@ -4273,6 +4279,7 @@
     private void handleDisplayAdded(int displayId) {
         synchronized (mService.mGlobalLock) {
             getActivityDisplayOrCreateLocked(displayId);
+            mService.mAm.startHomeActivityLocked(mCurrentUser, "displayAdded", displayId);
         }
     }
 
@@ -4838,7 +4845,8 @@
                 // We always want to return to the home activity instead of the recents activity
                 // from whatever is started from the recents activity, so move the home stack
                 // forward.
-                moveHomeStackToFront("startActivityFromRecents");
+                // TODO (b/115289124): Multi-display supports for recents.
+                getDefaultDisplay().moveHomeStackToFront("startActivityFromRecents");
             }
 
             // If the user must confirm credentials (e.g. when first launching a work app and the
@@ -4881,12 +4889,13 @@
                 final ActivityStack topSecondaryStack =
                         display.getTopStackInWindowingMode(WINDOWING_MODE_SPLIT_SCREEN_SECONDARY);
                 if (topSecondaryStack.isActivityTypeHome()) {
-                    // If the home activity if the top split-screen secondary stack, then the
+                    // If the home activity is the top split-screen secondary stack, then the
                     // primary split-screen stack is in the minimized mode which means it can't
                     // receive input keys, so we should move the focused app to the home app so that
                     // window manager can correctly calculate the focus window that can receive
                     // input keys.
-                    moveHomeStackToFront("startActivityFromRecents: homeVisibleInSplitScreen");
+                    display.moveHomeStackToFront(
+                            "startActivityFromRecents: homeVisibleInSplitScreen");
 
                     // Immediately update the minimized docked stack mode, the upcoming animation
                     // for the docked activity (WMS.overridePendingAppTransitionMultiThumbFuture)
diff --git a/services/core/java/com/android/server/am/ActivityStartController.java b/services/core/java/com/android/server/am/ActivityStartController.java
index 6e3a79c..5e73bc3 100644
--- a/services/core/java/com/android/server/am/ActivityStartController.java
+++ b/services/core/java/com/android/server/am/ActivityStartController.java
@@ -17,12 +17,14 @@
 package com.android.server.am;
 
 import static android.app.ActivityManager.START_SUCCESS;
+import static android.app.WindowConfiguration.ACTIVITY_TYPE_HOME;
+import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
 import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 
 import static com.android.server.am.ActivityManagerDebugConfig.TAG_AM;
 import static com.android.server.am.ActivityManagerDebugConfig.TAG_WITH_CLASS_NAME;
-import static android.app.ActivityManagerInternal.ALLOW_FULL_ONLY;
 
+import android.app.ActivityOptions;
 import android.app.IApplicationThread;
 import android.content.ComponentName;
 import android.content.ContentResolver;
@@ -75,7 +77,7 @@
     /** Temporary array to capture start activity results */
     private ActivityRecord[] tmpOutRecord = new ActivityRecord[1];
 
-    /**The result of the last home activity we attempted to start. */
+    /** The result of the last home activity we attempted to start. */
     private int mLastHomeActivityStartResult;
 
     /** A list of activities that are waiting to launch. */
@@ -161,13 +163,20 @@
         mLastStarter.postStartActivityProcessing(r, result, targetStack);
     }
 
-    void startHomeActivity(Intent intent, ActivityInfo aInfo, String reason) {
-        mSupervisor.moveHomeStackTaskToTop(reason);
+    void startHomeActivity(Intent intent, ActivityInfo aInfo, String reason, int displayId) {
+        if (!mSupervisor.canStartHomeOnDisplay(aInfo, displayId)) {
+            return;
+        }
 
+        final ActivityOptions options = ActivityOptions.makeBasic();
+        options.setLaunchWindowingMode(WINDOWING_MODE_FULLSCREEN);
+        options.setLaunchActivityType(ACTIVITY_TYPE_HOME);
+        options.setLaunchDisplayId(displayId);
         mLastHomeActivityStartResult = obtainStarter(intent, "startHomeActivity: " + reason)
                 .setOutActivity(tmpOutRecord)
                 .setCallingUid(0)
                 .setActivityInfo(aInfo)
+                .setActivityOptions(options.toBundle())
                 .execute();
         mLastHomeActivityStartRecord = tmpOutRecord[0];
         if (mSupervisor.inResumeTopActivity) {
diff --git a/services/core/java/com/android/server/am/ActivityStartInterceptor.java b/services/core/java/com/android/server/am/ActivityStartInterceptor.java
index 1fb8f87..4789ff3 100644
--- a/services/core/java/com/android/server/am/ActivityStartInterceptor.java
+++ b/services/core/java/com/android/server/am/ActivityStartInterceptor.java
@@ -277,7 +277,7 @@
             mActivityOptions = ActivityOptions.makeBasic();
         }
 
-        ActivityRecord homeActivityRecord = mSupervisor.getHomeActivity();
+        ActivityRecord homeActivityRecord = mSupervisor.getDefaultDisplayHomeActivity();
         if (homeActivityRecord != null && homeActivityRecord.getTask() != null) {
             // Showing credential confirmation activity in home task to avoid stopping multi-windowed
             // mode after showing the full-screen credential confirmation activity.
diff --git a/services/core/java/com/android/server/am/ActivityStarter.java b/services/core/java/com/android/server/am/ActivityStarter.java
index 8236bd0..de3b9cf 100644
--- a/services/core/java/com/android/server/am/ActivityStarter.java
+++ b/services/core/java/com/android/server/am/ActivityStarter.java
@@ -975,7 +975,8 @@
                             clearedTask);
                     break;
                 case WINDOWING_MODE_SPLIT_SCREEN_PRIMARY:
-                    final ActivityStack homeStack = mSupervisor.mHomeStack;
+                    final ActivityStack homeStack =
+                            startedActivityStack.getDisplay().getHomeStack();
                     if (homeStack != null && homeStack.shouldBeVisible(null /* starting */)) {
                         mService.mWindowManager.showRecentApps();
                     }
@@ -1280,6 +1281,15 @@
         setInitialState(r, options, inTask, doResume, startFlags, sourceRecord, voiceSession,
                 voiceInteractor);
 
+        // Do not start home activity if it cannot be launched on preferred display. We are not
+        // doing this in ActivityStackSupervisor#canPlaceEntityOnDisplay because it might
+        // fallback to launch on other displays.
+        if (r.isActivityTypeHome()
+                && !mSupervisor.canStartHomeOnDisplay(r.info, mPreferredDisplayId)) {
+            Slog.w(TAG, "Cannot launch home on display " + mPreferredDisplayId);
+            return START_CANCELED;
+        }
+
         computeLaunchingTaskFlags();
 
         computeSourceStack();
@@ -1430,7 +1440,11 @@
                 && top.userId == mStartActivity.userId
                 && top.attachedToProcess()
                 && ((mLaunchFlags & FLAG_ACTIVITY_SINGLE_TOP) != 0
-                || isLaunchModeOneOf(LAUNCH_SINGLE_TOP, LAUNCH_SINGLE_TASK));
+                || isLaunchModeOneOf(LAUNCH_SINGLE_TOP, LAUNCH_SINGLE_TASK))
+                // This allows home activity to automatically launch on secondary display when
+                // display added, if home was the top activity on default display, instead of
+                // sending new intent to the home activity on default display.
+                && (!top.isActivityTypeHome() || top.getDisplayId() == mPreferredDisplayId);
         if (dontStart) {
             // For paranoia, make sure we have correctly resumed the top activity.
             topStack.mLastPausedActivity = null;
@@ -1858,6 +1872,13 @@
                 intentActivity = mSupervisor.findTaskLocked(mStartActivity, mPreferredDisplayId);
             }
         }
+
+        if (mStartActivity.isActivityTypeHome() && intentActivity != null
+                && intentActivity.getDisplayId() != mPreferredDisplayId) {
+            // Do not reuse home activity on other displays.
+            intentActivity = null;
+        }
+
         return intentActivity;
     }
 
diff --git a/services/core/java/com/android/server/am/ActivityTaskManagerService.java b/services/core/java/com/android/server/am/ActivityTaskManagerService.java
index 36261b5..bb940cb 100644
--- a/services/core/java/com/android/server/am/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityTaskManagerService.java
@@ -1692,8 +1692,7 @@
                     return;
                 }
                 final ActivityRecord r = stack.topRunningActivityLocked();
-                if (mStackSupervisor.moveFocusableActivityStackToFrontLocked(
-                        r, "setFocusedStack")) {
+                if (mStackSupervisor.moveFocusableActivityToTop(r, "setFocusedStack")) {
                     mStackSupervisor.resumeFocusedStacksTopActivitiesLocked();
                 }
             }
@@ -1714,7 +1713,7 @@
                     return;
                 }
                 final ActivityRecord r = task.topRunningActivityLocked();
-                if (mStackSupervisor.moveFocusableActivityStackToFrontLocked(r, "setFocusedTask")) {
+                if (mStackSupervisor.moveFocusableActivityToTop(r, "setFocusedTask")) {
                     mStackSupervisor.resumeFocusedStacksTopActivitiesLocked();
                 }
             }
@@ -5263,7 +5262,8 @@
         @Override
         public ComponentName getHomeActivityForUser(int userId) {
             synchronized (mGlobalLock) {
-                ActivityRecord homeActivity = mStackSupervisor.getHomeActivityForUser(userId);
+                ActivityRecord homeActivity =
+                        mStackSupervisor.getDefaultDisplayHomeActivityForUser(userId);
                 return homeActivity == null ? null : homeActivity.realActivity;
             }
         }
@@ -5437,8 +5437,7 @@
                     throw new IllegalArgumentException(
                             "setFocusedActivity: No activity record matching token=" + token);
                 }
-                if (mStackSupervisor.moveFocusableActivityStackToFrontLocked(
-                        r, "setFocusedActivity")) {
+                if (mStackSupervisor.moveFocusableActivityToTop(r, "setFocusedActivity")) {
                     mStackSupervisor.resumeFocusedStacksTopActivitiesLocked();
                 }
             }
diff --git a/services/core/java/com/android/server/am/RecentTasks.java b/services/core/java/com/android/server/am/RecentTasks.java
index bd0eca8..4d0b1da 100644
--- a/services/core/java/com/android/server/am/RecentTasks.java
+++ b/services/core/java/com/android/server/am/RecentTasks.java
@@ -31,6 +31,8 @@
 import static android.content.Intent.FLAG_ACTIVITY_NEW_DOCUMENT;
 import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static android.os.Process.SYSTEM_UID;
+import static android.view.Display.DEFAULT_DISPLAY;
+
 import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_RECENTS;
 import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_RECENTS_TRIM_TASKS;
 import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_TASKS;
@@ -1242,7 +1244,6 @@
      */
     protected boolean isTrimmable(TaskRecord task) {
         final ActivityStack stack = task.getStack();
-        final ActivityStack homeStack = mSupervisor.mHomeStack;
 
         // No stack for task, just trim it
         if (stack == null) {
@@ -1250,13 +1251,14 @@
         }
 
         // Ignore tasks from different displays
-        if (stack.getDisplay() != homeStack.getDisplay()) {
+        // TODO (b/115289124): No Recents on non-default displays.
+        if (stack.mDisplayId != DEFAULT_DISPLAY) {
             return false;
         }
 
         // Trim tasks that are in stacks that are behind the home stack
         final ActivityDisplay display = stack.getDisplay();
-        return display.getIndexOf(stack) < display.getIndexOf(homeStack);
+        return display.getIndexOf(stack) < display.getIndexOf(display.getHomeStack());
     }
 
     /**
diff --git a/services/core/java/com/android/server/display/DisplayDeviceInfo.java b/services/core/java/com/android/server/display/DisplayDeviceInfo.java
index 512e851..c51dc52 100644
--- a/services/core/java/com/android/server/display/DisplayDeviceInfo.java
+++ b/services/core/java/com/android/server/display/DisplayDeviceInfo.java
@@ -110,6 +110,13 @@
     public static final int FLAG_MASK_DISPLAY_CUTOUT = 1 << 11;
 
     /**
+     * Flag: This flag identifies secondary displays that should show system decorations, such as
+     * status bar, navigation bar, home activity or IME.
+     * @hide
+     */
+    public static final int FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS = 1 << 12;
+
+    /**
      * Touch attachment: Display does not receive touch.
      */
     public static final int TOUCH_NONE = 0;
diff --git a/services/core/java/com/android/server/display/LogicalDisplay.java b/services/core/java/com/android/server/display/LogicalDisplay.java
index 5b7c520..6f726e6 100644
--- a/services/core/java/com/android/server/display/LogicalDisplay.java
+++ b/services/core/java/com/android/server/display/LogicalDisplay.java
@@ -18,7 +18,6 @@
 
 import android.graphics.Rect;
 import android.hardware.display.DisplayManagerInternal;
-import android.os.SystemProperties;
 import android.view.Display;
 import android.view.DisplayInfo;
 import android.view.Surface;
@@ -256,6 +255,9 @@
             if ((deviceInfo.flags & DisplayDeviceInfo.FLAG_CAN_SHOW_WITH_INSECURE_KEYGUARD) != 0) {
                 mBaseDisplayInfo.flags |= Display.FLAG_CAN_SHOW_WITH_INSECURE_KEYGUARD;
             }
+            if ((deviceInfo.flags & DisplayDeviceInfo.FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS) != 0) {
+                mBaseDisplayInfo.flags |= Display.FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS;
+            }
             Rect maskingInsets = getMaskingInsets(deviceInfo);
             int maskedWidth = deviceInfo.width - maskingInsets.left - maskingInsets.right;
             int maskedHeight = deviceInfo.height - maskingInsets.top - maskingInsets.bottom;
diff --git a/services/core/java/com/android/server/display/VirtualDisplayAdapter.java b/services/core/java/com/android/server/display/VirtualDisplayAdapter.java
index 244c764..5aa585f 100644
--- a/services/core/java/com/android/server/display/VirtualDisplayAdapter.java
+++ b/services/core/java/com/android/server/display/VirtualDisplayAdapter.java
@@ -17,14 +17,13 @@
 package com.android.server.display;
 
 import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR;
-import static android.hardware.display.DisplayManager
-        .VIRTUAL_DISPLAY_FLAG_CAN_SHOW_WITH_INSECURE_KEYGUARD;
-import static android.hardware.display.DisplayManager
-        .VIRTUAL_DISPLAY_FLAG_DESTROY_CONTENT_ON_REMOVAL;
+import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_CAN_SHOW_WITH_INSECURE_KEYGUARD;
+import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_DESTROY_CONTENT_ON_REMOVAL;
 import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_PRESENTATION;
 import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_PUBLIC;
 import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_ROTATES_WITH_CONTENT;
 import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_SECURE;
+import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS;
 import static android.hardware.display.DisplayManager.VIRTUAL_DISPLAY_FLAG_SUPPORTS_TOUCH;
 
 import android.content.Context;
@@ -367,7 +366,10 @@
                     mInfo.flags |= DisplayDeviceInfo.FLAG_ROTATES_WITH_CONTENT;
                 }
                 if ((mFlags & VIRTUAL_DISPLAY_FLAG_DESTROY_CONTENT_ON_REMOVAL) != 0) {
-                  mInfo.flags |= DisplayDeviceInfo.FLAG_DESTROY_CONTENT_ON_REMOVAL;
+                    mInfo.flags |= DisplayDeviceInfo.FLAG_DESTROY_CONTENT_ON_REMOVAL;
+                }
+                if ((mFlags & VIRTUAL_DISPLAY_FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS) != 0) {
+                    mInfo.flags |= DisplayDeviceInfo.FLAG_SHOULD_SHOW_SYSTEM_DECORATIONS;
                 }
 
                 mInfo.type = Display.TYPE_VIRTUAL;
diff --git a/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java b/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java
index 22add01..20088619 100644
--- a/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java
+++ b/services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java
@@ -168,6 +168,9 @@
         // Makes sure the supervisor is using with the spy object.
         atm.mStackSupervisor.setService(atm);
         doReturn(mock(IPackageManager.class)).when(am).getPackageManager();
+        PackageManagerInternal mockPackageManager = mock(PackageManagerInternal.class);
+        doReturn(mockPackageManager).when(am).getPackageManagerInternalLocked();
+        doReturn(null).when(mockPackageManager).getDefaultHomeActivity(anyInt());
         doNothing().when(am).grantEphemeralAccessLocked(anyInt(), any(), anyInt(), anyInt());
         am.mWindowManager = prepareMockWindowManager();
         atm.setWindowManager(am.mWindowManager);
@@ -175,10 +178,9 @@
         // Put a home stack on the default display, so that we'll always have something focusable.
         final TestActivityStackSupervisor supervisor =
                 (TestActivityStackSupervisor) atm.mStackSupervisor;
-        supervisor.mHomeStack = supervisor.mDisplay.createStack(WINDOWING_MODE_FULLSCREEN,
-                ACTIVITY_TYPE_HOME, ON_TOP);
+        supervisor.mDisplay.createStack(WINDOWING_MODE_FULLSCREEN, ACTIVITY_TYPE_HOME, ON_TOP);
         final TaskRecord task = new TaskBuilder(atm.mStackSupervisor)
-                .setStack(supervisor.mHomeStack).build();
+                .setStack(supervisor.getDefaultDisplay().getHomeStack()).build();
         new ActivityBuilder(atm).setTask(task).build();
     }
 
@@ -447,9 +449,6 @@
             final ActivityStackSupervisor supervisor = spy(createTestSupervisor());
             final KeyguardController keyguardController = mock(KeyguardController.class);
 
-            // No home stack is set.
-            doNothing().when(supervisor).moveHomeStackToFront(any());
-            doReturn(true).when(supervisor).moveHomeStackTaskToTop(any());
             // Invoked during {@link ActivityStack} creation.
             doNothing().when(supervisor).updateUIDsPresentOnDisplay();
             // Always keep things awake.
diff --git a/services/tests/servicestests/src/com/android/server/am/RecentTasksTest.java b/services/tests/servicestests/src/com/android/server/am/RecentTasksTest.java
index 70cfad1..1276f65 100644
--- a/services/tests/servicestests/src/com/android/server/am/RecentTasksTest.java
+++ b/services/tests/servicestests/src/com/android/server/am/RecentTasksTest.java
@@ -125,7 +125,6 @@
                 WINDOWING_MODE_FULLSCREEN, ACTIVITY_TYPE_HOME, true /* onTop */);
         mStack = mService.mStackSupervisor.getDefaultDisplay().createStack(
                 WINDOWING_MODE_FULLSCREEN, ACTIVITY_TYPE_STANDARD, true /* onTop */);
-        ((MyTestActivityStackSupervisor) mService.mStackSupervisor).setHomeStack(mHomeStack);
         mCallbacksRecorder = new CallbacksRecorder();
         mRecentTasks.registerCallback(mCallbacksRecorder);
         QUIET_USER_INFO.flags = UserInfo.FLAG_MANAGED_PROFILE | UserInfo.FLAG_QUIET_MODE;
@@ -558,9 +557,8 @@
 
         final MyTestActivityStackSupervisor supervisor =
                 (MyTestActivityStackSupervisor) mService.mStackSupervisor;
-        final ActivityStack homeStack = new MyTestActivityStack(mDisplay, supervisor);
+        final ActivityStack homeStack = mDisplay.getHomeStack();
         final ActivityStack aboveHomeStack = new MyTestActivityStack(mDisplay, supervisor);
-        supervisor.setHomeStack(homeStack);
 
         // Add a number of tasks (beyond the max) but ensure that nothing is trimmed because all
         // the tasks belong in stacks above the home stack
@@ -579,9 +577,8 @@
         final MyTestActivityStackSupervisor supervisor =
                 (MyTestActivityStackSupervisor) mService.mStackSupervisor;
         final ActivityStack behindHomeStack = new MyTestActivityStack(mDisplay, supervisor);
-        final ActivityStack homeStack = new MyTestActivityStack(mDisplay, supervisor);
+        final ActivityStack homeStack = mDisplay.getHomeStack();
         final ActivityStack aboveHomeStack = new MyTestActivityStack(mDisplay, supervisor);
-        supervisor.setHomeStack(homeStack);
 
         // Add a number of tasks (beyond the max) but ensure that only the task in the stack behind
         // the home stack is trimmed once a new task is added
@@ -601,9 +598,8 @@
 
         final MyTestActivityStackSupervisor supervisor =
                 (MyTestActivityStackSupervisor) mService.mStackSupervisor;
-        final ActivityStack homeStack = new MyTestActivityStack(mDisplay, supervisor);
+        final ActivityStack homeStack = mDisplay.getHomeStack();
         final ActivityStack otherDisplayStack = new MyTestActivityStack(mOtherDisplay, supervisor);
-        supervisor.setHomeStack(homeStack);
 
         // Add a number of tasks (beyond the max) on each display, ensure that the tasks are not
         // removed
@@ -870,7 +866,7 @@
         @Override
         public void initialize() {
             super.initialize();
-            mDisplay = TestActivityDisplay.create(this, DEFAULT_DISPLAY);
+            mDisplay = getActivityDisplay(DEFAULT_DISPLAY);
             mOtherDisplay = TestActivityDisplay.create(this, DEFAULT_DISPLAY + 1);
             addChild(mOtherDisplay, ActivityDisplay.POSITION_TOP);
             addChild(mDisplay, ActivityDisplay.POSITION_TOP);
@@ -881,10 +877,6 @@
             mRunningTasks = new TestRunningTasks();
             return mRunningTasks;
         }
-
-        void setHomeStack(ActivityStack stack) {
-            mHomeStack = stack;
-        }
     }
 
     private class MyTestActivityStack extends TestActivityStack {