am 29961911: Merge "Fix music crash when search song."

* commit '2996191189a9104852eedf1c97b68b0259579586':
  Fix music crash when search song.
diff --git a/src/com/android/music/QueryBrowserActivity.java b/src/com/android/music/QueryBrowserActivity.java
index 977650c..fb29a3d 100644
--- a/src/com/android/music/QueryBrowserActivity.java
+++ b/src/com/android/music/QueryBrowserActivity.java
@@ -210,7 +210,9 @@
         // Because we pass the adapter to the next activity, we need to make
         // sure it doesn't keep a reference to this activity. We can do this
         // by clearing its DatasetObservers, which setListAdapter(null) does.
-        setListAdapter(null);
+        if (getListView() != null) {
+            setListAdapter(null);
+        }
         mAdapter = null;
         super.onDestroy();
     }