From 1bd14bc4e399ee6439b638f7bc0077879da38899 Mon Sep 17 00:00:00 2001
From: Jorge Gil <jorgegil@google.com>
Date: Thu, 4 May 2023 02:36:19 +0000
Subject: Do not create window decorations for split roots

Split roots (either the single-top root or stage roots) were usually
excluded from having window decorations by the exclusion logic for
non-leafs that exists in FreeformTaskTransitionObserver. However,
once split is dismissed and the child tasks are reparented out of the
stages, the two stage roots become leafs and if they were included as
part of a transition, a window decoration was being created for each of
them. This change excludes split roots from having a window decoration.

Bug: 280499263
Test: enter split, dismiss split by dragging the divider, observe
there's no crash

Change-Id: I4d563176a75512232fc853232b3666d511e4c922
---
 .../com/android/wm/shell/splitscreen/SplitScreenController.java    | 5 +++++
 .../src/com/android/wm/shell/splitscreen/StageCoordinator.java     | 7 +++++++
 .../src/com/android/wm/shell/splitscreen/StageTaskListener.java    | 4 ++++
 .../wm/shell/windowdecor/DesktopModeWindowDecorViewModel.java      | 4 ++++
 4 files changed, 20 insertions(+)

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/SplitScreenController.java b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/SplitScreenController.java
index af52350f5b48..c654c1b0d431 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/SplitScreenController.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/SplitScreenController.java
@@ -337,6 +337,11 @@ public class SplitScreenController implements DragAndDropPolicy.Starter,
         return isTaskInSplitScreen(taskId) && isSplitScreenVisible();
     }
 
+    /** Check whether the task is the single-top root or the root of one of the stages. */
+    public boolean isTaskRootOrStageRoot(int taskId) {
+        return mStageCoordinator.isRootOrStageRoot(taskId);
+    }
+
     public @SplitPosition int getSplitPosition(int taskId) {
         return mStageCoordinator.getSplitPosition(taskId);
     }
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java
index b8373f3548ca..749549d1ca55 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java
@@ -377,6 +377,13 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
         return STAGE_TYPE_UNDEFINED;
     }
 
+    boolean isRootOrStageRoot(int taskId) {
+        if (mRootTaskInfo != null && mRootTaskInfo.taskId == taskId) {
+            return true;
+        }
+        return mMainStage.isRootTaskId(taskId) || mSideStage.isRootTaskId(taskId);
+    }
+
     boolean moveToStage(ActivityManager.RunningTaskInfo task, @SplitPosition int stagePosition,
             WindowContainerTransaction wct) {
         prepareEnterSplitScreen(wct, task, stagePosition);
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageTaskListener.java b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageTaskListener.java
index 18b09b090794..e2e9270cd6cc 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageTaskListener.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageTaskListener.java
@@ -286,6 +286,10 @@ class StageTaskListener implements ShellTaskOrganizer.TaskListener {
         }
     }
 
+    boolean isRootTaskId(int taskId) {
+        return mRootTaskInfo != null && mRootTaskInfo.taskId == taskId;
+    }
+
     void onResizing(Rect newBounds, Rect sideBounds, SurfaceControl.Transaction t, int offsetX,
             int offsetY, boolean immediately) {
         if (mSplitDecorManager != null && mRootTaskInfo != null) {
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecorViewModel.java b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecorViewModel.java
index 0b821844e46c..54babce13205 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecorViewModel.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/DesktopModeWindowDecorViewModel.java
@@ -760,6 +760,10 @@ public class DesktopModeWindowDecorViewModel implements WindowDecorViewModel {
 
     private boolean shouldShowWindowDecor(RunningTaskInfo taskInfo) {
         if (taskInfo.getWindowingMode() == WINDOWING_MODE_FREEFORM) return true;
+        if (mSplitScreenController.isPresent()
+                && mSplitScreenController.get().isTaskRootOrStageRoot(taskInfo.taskId)) {
+            return false;
+        }
         return DesktopModeStatus.isProto2Enabled()
                 && taskInfo.getActivityType() == ACTIVITY_TYPE_STANDARD
                 && mDisplayController.getDisplayContext(taskInfo.displayId)
-- 
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