sync compositor: pass simple gfx types by const ref

content/public/browser/android/synchronous_compositor_client.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_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_CLIENT_H_
 #define CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_CLIENT_H_
 
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/time/time.h"
@@ skipping 17 matching lines @@
   virtual void DidDestroyCompositor(SynchronousCompositor* compositor) = 0;
 
   // See LayerScrollOffsetDelegate for details.
   virtual void UpdateRootLayerState(const gfx::Vector2dF& total_scroll_offset,
                                     const gfx::Vector2dF& max_scroll_offset,
                                     const gfx::SizeF& scrollable_size,
                                     float page_scale_factor,
                                     float min_page_scale_factor,
                                     float max_page_scale_factor) = 0;
 
-  virtual void DidOverscroll(gfx::Vector2dF accumulated_overscroll,
-                             gfx::Vector2dF latest_overscroll_delta,
-                             gfx::Vector2dF current_fling_velocity) = 0;
+  virtual void DidOverscroll(const gfx::Vector2dF& accumulated_overscroll,
+                             const gfx::Vector2dF& latest_overscroll_delta,
+                             const gfx::Vector2dF& current_fling_velocity) = 0;
 
   virtual void PostInvalidate() = 0;
 
   virtual void DidUpdateContent() = 0;
 
  protected:
   SynchronousCompositorClient() {}
   virtual ~SynchronousCompositorClient() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SynchronousCompositorClient);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_CLIENT_H_