Merge "Move pip behind home stack on dismiss" into rvc-dev

services/core/java/com/android/server/wm/ActivityStack.java

@@ -943,19 +943,7 @@ class ActivityStack extends Task {
         // task's ordering. However, we still need to move 'task' to back. The intention is that
         // this ends up behind the home-task so that it is made invisible; so, if the home task
         // is not a child of this, reparent 'task' to the back of the home task's actual parent.
-        final ActivityStack home = displayArea.getOrCreateRootHomeTask();
+        displayArea.positionTaskBehindHome((ActivityStack) task);
-        final WindowContainer homeParent = home.getParent();
-        final Task homeParentTask = homeParent != null ? homeParent.asTask() : null;
-        if (homeParentTask == null) {
-            ((ActivityStack) task).reparent(displayArea, false /* onTop */);
-        } else if (homeParentTask == this) {
-            // Apparently reparent early-outs if same stack, so we have to explicitly reorder.
-            positionChildAtBottom(task);
-        } else {
-            task.reparent((ActivityStack) homeParentTask, false /* toTop */,
-                    REPARENT_LEAVE_STACK_IN_PLACE, false /* animate */, false /* deferResume */,
-                    "moveToBack");
-        }
     }
 
     // TODO: Should each user have there own stacks?

services/core/java/com/android/server/wm/ActivityStackSupervisor.java

@@ -1441,11 +1441,7 @@ public class ActivityStackSupervisor implements RecentTasks.Callbacks {
         try {
             stack.setWindowingMode(WINDOWING_MODE_UNDEFINED);
             stack.setBounds(null);
-            if (toDisplay.getDisplayId() != stack.getDisplayId()) {
+            toDisplay.getDefaultTaskDisplayArea().positionTaskBehindHome(stack);
-                stack.reparent(toDisplay.getDefaultTaskDisplayArea(), false /* onTop */);
-            } else {
-                toDisplay.getDefaultTaskDisplayArea().positionStackAtBottom(stack);
-            }
 
             // Follow on the workaround: activities are kept force hidden till the new windowing
             // mode is set.

services/core/java/com/android/server/wm/TaskDisplayArea.java

@@ -765,6 +765,32 @@ final class TaskDisplayArea extends DisplayArea<ActivityStack> {
         onStackOrderChanged(stack);
     }
 
+    /**
+     * Moves/reparents `task` to the back of whatever container the home stack is in. This is for
+     * when we just want to move a task to "the back" vs. a specific place. The primary use-case
+     * is to make sure that moved-to-back apps go into secondary split when in split-screen mode.
+     */
+    void positionTaskBehindHome(ActivityStack task) {
+        final ActivityStack home = getOrCreateRootHomeTask();
+        final WindowContainer homeParent = home.getParent();
+        final Task homeParentTask = homeParent != null ? homeParent.asTask() : null;
+        if (homeParentTask == null) {
+            // reparent throws if parent didn't change...
+            if (task.getParent() == this) {
+                positionStackAtBottom(task);
+            } else {
+                task.reparent(this, false /* onTop */);
+            }
+        } else if (homeParentTask == task.getParent()) {
+            // Apparently reparent early-outs if same stack, so we have to explicitly reorder.
+            ((ActivityStack) homeParentTask).positionChildAtBottom(task);
+        } else {
+            task.reparent((ActivityStack) homeParentTask, false /* toTop */,
+                    Task.REPARENT_LEAVE_STACK_IN_PLACE, false /* animate */,
+                    false /* deferResume */, "positionTaskBehindHome");
+        }
+    }
+
     ActivityStack getStack(int rootTaskId) {
         for (int i = getStackCount() - 1; i >= 0; --i) {
             final ActivityStack stack = getStackAt(i);