From 20a817a198b1cc9711e0b03b20e8a792f5518c2d Mon Sep 17 00:00:00 2001
From: Evan Rosky <erosky@google.com>
Date: Tue, 22 Jun 2021 19:22:06 -0700
Subject: [PATCH] Fix rotation shell transition

The old freeze/legacy display rotation logic was running with
shell transitions enabled. Additionally, WindowState.removeImmediately
was removing its child surface in the wrong order causing it to not
be removed on the sync transaction and yielding several frames of
blackness.

Bug: 190002115
Test: enable shell transitions, launch a rotatable app (like messages),
      rotate device. Observe a jumpcut without black flicker.
Change-Id: Ia2ce00b1cf4317c6678e6b5f91407296b23cc87e
---
 .../core/java/com/android/server/wm/ActivityRecord.java   | 4 +++-
 services/core/java/com/android/server/wm/WindowState.java | 8 ++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/wm/ActivityRecord.java b/services/core/java/com/android/server/wm/ActivityRecord.java
index a16d6fe11902c..6970c63d71354 100644
--- a/services/core/java/com/android/server/wm/ActivityRecord.java
+++ b/services/core/java/com/android/server/wm/ActivityRecord.java
@@ -8151,7 +8151,9 @@ final class ActivityRecord extends WindowToken implements WindowManagerService.A
         if (shouldRelaunchLocked(changes, mTmpConfig) || forceNewConfig) {
             // Aha, the activity isn't handling the change, so DIE DIE DIE.
             configChangeFlags |= changes;
-            startFreezingScreenLocked(globalChanges);
+            if (!mAtmService.getTransitionController().isShellTransitionsEnabled()) {
+                startFreezingScreenLocked(globalChanges);
+            }
             forceNewConfig = false;
             preserveWindow &= isResizeOnlyChange(changes);
             final boolean hasResizeChange = hasResizeChange(changes & ~info.getRealConfigChanged());
diff --git a/services/core/java/com/android/server/wm/WindowState.java b/services/core/java/com/android/server/wm/WindowState.java
index 309ceb273907b..10e2486651903 100644
--- a/services/core/java/com/android/server/wm/WindowState.java
+++ b/services/core/java/com/android/server/wm/WindowState.java
@@ -2390,6 +2390,12 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
 
     @Override
     void removeImmediately() {
+        if (!mRemoved) {
+            // Destroy surface before super call. The general pattern is that the children need
+            // to be removed before the parent (so that the sync-engine tracking works). Since
+            // WindowStateAnimator is a "virtual" child, we have to do it manually here.
+            mWinAnimator.destroySurfaceLocked(getSyncTransaction());
+        }
         super.removeImmediately();
 
         if (mRemoved) {
@@ -2431,8 +2437,6 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
 
         disposeInputChannel();
 
-        mWinAnimator.destroySurfaceLocked(mTmpTransaction);
-        mTmpTransaction.apply();
         mSession.windowRemovedLocked();
         try {
             mClient.asBinder().unlinkToDeath(mDeathRecipient, 0);