Don't allow removed DividerView to resize stack

If a divider view is removed or in the process of been removed, then it
should no longer have any influence on the size of stacks.

Fixes: 62273599
Test: go/wm-smoke
Test: enter split-screen and make sure recents is visible, lock and
unlock the device and verify things look fine.

Change-Id: I79aca82be8a7013328b78e82f508c4ed9fa48a4a

2 files changed, 15 insertions, 0 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/stackdivider/Divider.java b/packages/SystemUI/src/com/android/systemui/stackdivider/Divider.java
index 0b09accf2db1..3b37437bfca0 100644
--- a/packages/SystemUI/src/com/android/systemui/stackdivider/Divider.java
+++ b/packages/SystemUI/src/com/android/systemui/stackdivider/Divider.java
@@ -91,6 +91,9 @@ public class Divider extends SystemUI {
     }
 
     private void removeDivider() {
+        if (mView != null) {
+            mView.onDividerRemoved();
+        }
         mWindowManager.remove();
     }
 
diff --git a/packages/SystemUI/src/com/android/systemui/stackdivider/DividerView.java b/packages/SystemUI/src/com/android/systemui/stackdivider/DividerView.java
index 9e2ec571faa8..6dc7870770a5 100644
--- a/packages/SystemUI/src/com/android/systemui/stackdivider/DividerView.java
+++ b/packages/SystemUI/src/com/android/systemui/stackdivider/DividerView.java
@@ -162,6 +162,9 @@ public class DividerView extends FrameLayout implements OnTouchListener,
     private DividerState mState;
     private final SurfaceFlingerVsyncChoreographer mSfChoreographer;
 
+    // The view is removed or in the process of been removed from the system.
+    private boolean mRemoved;
+
     private final Handler mHandler = new Handler() {
         @Override
         public void handleMessage(Message msg) {
@@ -323,6 +326,11 @@ public class DividerView extends FrameLayout implements OnTouchListener,
         EventBus.getDefault().unregister(this);
     }
 
+    void onDividerRemoved() {
+        mRemoved = true;
+        mHandler.removeMessages(MSG_RESIZE_STACK);
+    }
+
     @Override
     public WindowInsets onApplyWindowInsets(WindowInsets insets) {
         if (mStableInsets.left != insets.getStableInsetLeft()
@@ -917,6 +925,10 @@ public class DividerView extends FrameLayout implements OnTouchListener,
     }
 
     public void resizeStack(int position, int taskPosition, SnapTarget taskSnapTarget) {
+        if (mRemoved) {
+            // This divider view has been removed so shouldn't have any additional influence.
+            return;
+        }
         calculateBoundsForPosition(position, mDockSide, mDockedRect);
 
         if (mDockedRect.equals(mLastResizeRect) && !mEntranceAnimationRunning) {