Merge "Fix exception when trying to update config of detached stack" into nyc-dev

am: a1984286d3

* commit 'a1984286d397e4198d4e26572fb54cd55dce6d20':
  Fix exception when trying to update config of detached stack

Change-Id: I293ac1716f7c05677ce90e7cceaf8b094be3ca97

services/core/java/com/android/server/wm/TaskStack.java

@@ -381,6 +381,11 @@ public class TaskStack implements DimLayer.DimLayerUser,
     }
 
     private boolean updateBoundsAfterConfigChange() {
+        if (mDisplayContent == null) {
+            // If the stack is already detached we're not updating anything,
+            // as it's going away soon anyway.
+            return false;
+        }
         final int newRotation = getDisplayInfo().rotation;
         final int newDensity = getDisplayInfo().logicalDensityDpi;