Fix NPE when mAdapter is null

Bug:17414016
Change-Id: Id35d0de1a48b38bb4ef32c3f89e47bf2c374dda5
diff --git a/src/com/android/contacts/common/list/PinnedHeaderListView.java b/src/com/android/contacts/common/list/PinnedHeaderListView.java
index cc31cff..930f0d0 100644
--- a/src/com/android/contacts/common/list/PinnedHeaderListView.java
+++ b/src/com/android/contacts/common/list/PinnedHeaderListView.java
@@ -452,6 +452,9 @@
     };
 
     private boolean smoothScrollToPartition(int partition) {
+        if (mAdapter == null) {
+            return false;
+        }
         final int position = mAdapter.getScrollPositionForHeader(partition);
         if (position == -1) {
             return false;
@@ -571,4 +574,4 @@
             canvas.restoreToCount(saveCount);
         }
     }
-}
\ No newline at end of file
+}