Fix NPE in setTransparentRegion.

Check for null Surface before using it.

Fixes bug 6312835.

Change-Id: Iaaac2a5d88e81b88e369815e09818c268085e4b7

Author: Craig Mautner

services/java/com/android/server/wm/WindowManagerService.java

@@ -6897,8 +6897,6 @@ public void handleMessage(Message msg) {
                                 (Pair<WindowStateAnimator, Region>) msg.obj;
                     final WindowStateAnimator winAnimator = pair.first;
                     winAnimator.setTransparentRegionHint(pair.second);
-
-                    scheduleAnimationLocked();
                     break;
                 }
 

services/java/com/android/server/wm/WindowStateAnimator.java

@@ -943,6 +943,10 @@ public void prepareSurfaceLocked(final boolean recoveringMemory) {
     }
 
     void setTransparentRegionHint(final Region region) {
+        if (mSurface == null) {
+            Slog.w(TAG, "setTransparentRegionHint: null mSurface after mHasSurface true");
+            return;
+        }
         if (SHOW_LIGHT_TRANSACTIONS) Slog.i(TAG,
             ">>> OPEN TRANSACTION setTransparentRegion");
         Surface.openTransaction();