cc: Don't pass simple well-defined classes by reference.

cc/trees/layer_tree_host.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_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <limits>
 #include <vector>
 
@@ skipping 147 matching lines @@
   RenderingStatsInstrumentation* rendering_stats_instrumentation() const {
     return rendering_stats_instrumentation_.get();
   }
 
   const RendererCapabilities& GetRendererCapabilities() const;
 
   void SetNeedsAnimate();
   virtual void SetNeedsCommit();
   virtual void SetNeedsFullTreeSync();
   void SetNeedsRedraw();
-  void SetNeedsRedrawRect(const gfx::Rect& damage_rect);
+  void SetNeedsRedrawRect(gfx::Rect damage_rect);
   bool CommitRequested() const;
 
   void SetAnimationEvents(scoped_ptr<AnimationEventsVector> events,
                           base::Time wall_clock_time);
 
   void SetRootLayer(scoped_refptr<Layer> root_layer);
   Layer* root_layer() { return root_layer_.get(); }
   const Layer* root_layer() const { return root_layer_.get(); }
   const Layer* RootScrollLayer() const;
 
@@ skipping 163 matching lines @@
   bool in_paint_layer_contents_;
 
   LatencyInfo latency_info_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_