Add null check and call destroy from single point.

Ensure that calling destroy() on a DimLayer surface only happens
once.

Fixes bug 19660387.

Change-Id: Iee8ea20b5d7c3a8f81f14a3ecff66a1dc1a8d719

1 files changed, 10 insertions, 6 deletions

diff --git a/services/core/java/com/android/server/wm/TaskStack.java b/services/core/java/com/android/server/wm/TaskStack.java
index 6d09f55..b61a6f7 100644
--- a/services/core/java/com/android/server/wm/TaskStack.java
+++ b/services/core/java/com/android/server/wm/TaskStack.java
@@ -373,10 +373,8 @@ public class TaskStack {
             mService.requestTraversalLocked();
         }
 
-        mAnimationBackgroundSurface.destroySurface();
-        mAnimationBackgroundSurface = null;
-        mDimLayer.destroySurface();
-        mDimLayer = null;
+        close();
+
         mDisplayContent = null;
     }
 
@@ -501,8 +499,14 @@ public class TaskStack {
     }
 
     void close() {
-        mDimLayer.mDimSurface.destroy();
-        mAnimationBackgroundSurface.mDimSurface.destroy();
+        if (mAnimationBackgroundSurface != null) {
+            mAnimationBackgroundSurface.destroySurface();
+            mAnimationBackgroundSurface = null;
+        }
+        if (mDimLayer != null) {
+            mDimLayer.destroySurface();
+            mDimLayer = null;
+        }
     }
 
     public void dump(String prefix, PrintWriter pw) {