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

cc/trees/thread_proxy.h

Index: cc/trees/thread_proxy.h
diff --git a/cc/trees/thread_proxy.h b/cc/trees/thread_proxy.h
index 49cbb19df1169c280ff10aa2c7fc18a7cf4826ef..7da65a1835106447827ef55f3b2c8d489b9ef1dd 100644
--- a/cc/trees/thread_proxy.h
+++ b/cc/trees/thread_proxy.h
@@ -41,7 +41,8 @@ class ThreadProxy : public Proxy,
   virtual ~ThreadProxy();
 
   // Proxy implementation
-  virtual bool CompositeAndReadback(void* pixels, gfx::Rect rect) OVERRIDE;
+  virtual bool CompositeAndReadback(void* pixels,
+                                    const gfx::Rect& rect) OVERRIDE;
   virtual void FinishAllRendering() OVERRIDE;
   virtual bool IsStarted() const OVERRIDE;
   virtual void SetLayerTreeHostClientReady() OVERRIDE;
@@ -51,7 +52,7 @@ class ThreadProxy : public Proxy,
   virtual void SetNeedsAnimate() OVERRIDE;
   virtual void SetNeedsUpdateLayers() OVERRIDE;
   virtual void SetNeedsCommit() OVERRIDE;
-  virtual void SetNeedsRedraw(gfx::Rect damage_rect) OVERRIDE;
+  virtual void SetNeedsRedraw(const gfx::Rect& damage_rect) OVERRIDE;
   virtual void SetNextCommitWaitsForActivation() OVERRIDE;
   virtual void NotifyInputThrottledUntilCommit() OVERRIDE;
   virtual void SetDeferCommits(bool defer_commits) OVERRIDE;
@@ -77,7 +78,8 @@ class ThreadProxy : public Proxy,
   // Please call these 2 functions through
   // LayerTreeHostImpl's SetNeedsRedraw() and SetNeedsRedrawRect().
   virtual void SetNeedsRedrawOnImplThread() OVERRIDE;
-  virtual void SetNeedsRedrawRectOnImplThread(gfx::Rect dirty_rect) OVERRIDE;
+  virtual void SetNeedsRedrawRectOnImplThread(
+      const gfx::Rect& dirty_rect) OVERRIDE;
   virtual void SetNeedsManageTilesOnImplThread() OVERRIDE;
   virtual void DidInitializeVisibleTileOnImplThread() OVERRIDE;
   virtual void SetNeedsCommitOnImplThread() OVERRIDE;