Merge "PersistableBundle.restoreFromXml should return a mutable bundle." am: ffb1899ba2 am: c13f8d0fe7 am: e494cdfbb8

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1679293

Change-Id: Ib1e7197d38af8a4b5d0060c4cf3945c6ad3e847d

core/java/android/os/PersistableBundle.java

@@ -316,7 +316,7 @@ public final class PersistableBundle extends BaseBundle implements Cloneable, Pa
                         new MyReadMapCallback()));
             }
         }
-        return EMPTY;
+        return new PersistableBundle();  // An empty mutable PersistableBundle
     }
 
     @Override