Merge "Fix crash when docking." into nyc-dev am: 45ee78c

am: 6ad9739

* commit '6ad97390a3e319e32107ebaaacb6c273211d2153':
  Fix crash when docking.

Change-Id: Ic99f5ffe1c2e49cdc6503afefa9482e9b534d0d9

core/java/android/app/ActivityThread.java

@@ -3479,7 +3479,9 @@ public final class ActivityThread {
                     // the decor view we have to notify the view root that the
                     // callbacks may have changed.
                     ViewRootImpl impl = decor.getViewRootImpl();
-                    impl.notifyChildRebuilt();
+                    if (impl != null) {
+                        impl.notifyChildRebuilt();
+                    }
                 }
                 if (a.mVisibleFromClient && !a.mWindowAdded) {
                     a.mWindowAdded = true;