[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/trees/proxy.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 CC_TREES_PROXY_H_
 #define CC_TREES_PROXY_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 28 matching lines @@
   bool IsMainThread() const;
   bool IsImplThread() const;
   bool IsMainThreadBlocked() const;
 #ifndef NDEBUG
   void SetMainThreadBlocked(bool is_main_thread_blocked);
   void SetCurrentThreadIsImplThread(bool is_impl_thread);
 #endif
 
   virtual ~Proxy();
 
-  virtual bool CompositeAndReadback(void* pixels, gfx::Rect rect) = 0;
+  virtual bool CompositeAndReadback(void* pixels, const gfx::Rect& rect) = 0;
 
   virtual void FinishAllRendering() = 0;
 
   virtual bool IsStarted() const = 0;
 
   // Indicates that the compositing surface associated with our context is
   // ready to use.
   virtual void SetLayerTreeHostClientReady() = 0;
 
   virtual void SetVisible(bool visible) = 0;
 
   // Attempts to recreate the context and renderer synchronously after the
   // output surface is lost. Calls
   // LayerTreeHost::OnCreateAndInitializeOutputSurfaceAttempted with the result.
   virtual void CreateAndInitializeOutputSurface() = 0;
 
   virtual const RendererCapabilities& GetRendererCapabilities() const = 0;
 
   virtual void SetNeedsAnimate() = 0;
   virtual void SetNeedsUpdateLayers() = 0;
   virtual void SetNeedsCommit() = 0;
-  virtual void SetNeedsRedraw(gfx::Rect damage_rect) = 0;
+  virtual void SetNeedsRedraw(const gfx::Rect& damage_rect) = 0;
   virtual void SetNextCommitWaitsForActivation() = 0;
 
   virtual void NotifyInputThrottledUntilCommit() = 0;
 
   // Defers commits until it is reset. It is only supported when in threaded
   // mode. It's an error to make a sync call like CompositeAndReadback while
   // commits are deferred.
   virtual void SetDeferCommits(bool defer_commits) = 0;
 
   virtual void MainThreadHasStoppedFlinging() = 0;
@@ skipping 59 matching lines @@
   explicit DebugScopedSetMainThreadBlocked(Proxy* proxy) {}
   ~DebugScopedSetMainThreadBlocked() {}
  private:
   DISALLOW_COPY_AND_ASSIGN(DebugScopedSetMainThreadBlocked);
 };
 #endif
 
 }  // namespace cc
 
 #endif  // CC_TREES_PROXY_H_