[#6]Pass gfx structs by const ref (gfx::Vector2d)

content/test/web_layer_tree_view_impl_for_testing.h

 // Copyright 2013 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 CONTENT_TEST_WEB_LAYER_TREE_VIEW_IMPL_FOR_TESTING_H_
 #define CONTENT_TEST_WEB_LAYER_TREE_VIEW_IMPL_FOR_TESTING_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
@@ skipping 48 matching lines @@
       const blink::WebLayer* pageScaleLayerLayer,
       const blink::WebLayer* innerViewportScrollLayer,
       const blink::WebLayer* outerViewportScrollLayer) OVERRIDE;
   virtual void clearViewportLayers() OVERRIDE;
 
   // cc::LayerTreeHostClient implementation.
   virtual void WillBeginMainFrame(int frame_id) OVERRIDE {}
   virtual void DidBeginMainFrame() OVERRIDE {}
   virtual void Animate(double frame_begin_time) OVERRIDE {}
   virtual void Layout() OVERRIDE;
-  virtual void ApplyScrollAndScale(gfx::Vector2d scroll_delta, float page_scale)
-      OVERRIDE;
+  virtual void ApplyScrollAndScale(const gfx::Vector2d& scroll_delta,
+                                   float page_scale) OVERRIDE;
   virtual scoped_ptr<cc::OutputSurface> CreateOutputSurface(bool fallback)
       OVERRIDE;
   virtual void DidInitializeOutputSurface(bool success) OVERRIDE {}
   virtual void WillCommit() OVERRIDE {}
   virtual void DidCommit() OVERRIDE {}
   virtual void DidCommitAndDrawFrame() OVERRIDE {}
   virtual void DidCompleteSwapBuffers() OVERRIDE {}
   virtual scoped_refptr<cc::ContextProvider>
       OffscreenContextProvider() OVERRIDE;
 
   // cc::LayerTreeHostSingleThreadClient implementation.
   virtual void ScheduleComposite() OVERRIDE {}
   virtual void ScheduleAnimation() OVERRIDE {}
   virtual void DidPostSwapBuffers() OVERRIDE {}
   virtual void DidAbortSwapBuffers() OVERRIDE {}
 
  private:
   scoped_ptr<cc::LayerTreeHost> layer_tree_host_;
 
   DISALLOW_COPY_AND_ASSIGN(WebLayerTreeViewImplForTesting);
 };
 
 }  // namespace webkit
 
 #endif  // CONTENT_TEST_WEB_LAYER_TREE_VIEW_IMPL_FOR_TESTING_H_