Address warnings from clang build bot

http://codereview.appspot.com/6506111/



git-svn-id: http://skia.googlecode.com/svn/trunk@5518 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/animator/SkDrawGroup.h b/src/animator/SkDrawGroup.h
index 8124650..a63a50e 100644
--- a/src/animator/SkDrawGroup.h
+++ b/src/animator/SkDrawGroup.h
@@ -19,7 +19,7 @@
     DECLARE_MEMBER_INFO(Group);
     SkGroup();
     virtual ~SkGroup();
-    virtual bool add(SkAnimateMaker& , SkDisplayable* child);
+    virtual bool add(SkAnimateMaker& , SkDisplayable* child) SK_OVERRIDE;
     virtual bool contains(SkDisplayable* );
     SkGroup* copy();
     SkBool copySet(int index);