Fix CC*Renderer and CC*LayerImpl to compile with Clang

cc/CCTiledLayerImpl.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CCTiledLayerImpl_h
 #define CCTiledLayerImpl_h
 
 #include "CCLayerImpl.h"
 #include <public/WebTransformationMatrix.h>
 
@@ skipping 27 matching lines @@
     virtual void didLoseContext() OVERRIDE;
 
 protected:
     explicit CCTiledLayerImpl(int id);
     // Exposed for testing.
     bool hasTileAt(int, int) const;
     bool hasTextureIdForTileAt(int, int) const;
 
 private:
 
-    virtual const char* layerTypeAsString() const OVERRIDE { return "ContentLayer"; }
+    virtual const char* layerTypeAsString() const OVERRIDE;
 
     DrawableTile* tileAt(int, int) const;
     DrawableTile* createTile(int, int);
 
     bool m_skipsDraw;
     bool m_contentsSwizzled;
 
     OwnPtr<CCLayerTilingData> m_tiler;
 };
 
 }
 
 #endif // CCTiledLayerImpl_h