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

cc/debug/debug_rect_history.h

 // Copyright 2012 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_DEBUG_DEBUG_RECT_HISTORY_H_
 #define CC_DEBUG_DEBUG_RECT_HISTORY_H_
 
 #include <vector>
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 39 matching lines @@
   REPLICA_SCREEN_SPACE_RECT_TYPE,
   OCCLUDING_RECT_TYPE,
   NONOCCLUDING_RECT_TYPE,
   TOUCH_EVENT_HANDLER_RECT_TYPE,
   WHEEL_EVENT_HANDLER_RECT_TYPE,
   NON_FAST_SCROLLABLE_RECT_TYPE,
   ANIMATION_BOUNDS_RECT_TYPE,
 };
 
 struct DebugRect {
-  DebugRect(DebugRectType new_type, gfx::RectF new_rect)
+  DebugRect(DebugRectType new_type, const gfx::RectF& new_rect)
       : type(new_type), rect(new_rect) {}
 
   DebugRectType type;
   gfx::RectF rect;
 };
 
 // This class maintains a history of rects of various types that can be used
 // for debugging purposes. The overhead of collecting rects is performed only if
 // the appropriate LayerTreeSettings are enabled.
 class DebugRectHistory {
@@ skipping 37 matching lines @@
       const LayerImplList& render_surface_layer_list);
 
   std::vector<DebugRect> debug_rects_;
 
   DISALLOW_COPY_AND_ASSIGN(DebugRectHistory);
 };
 
 }  // namespace cc
 
 #endif  // CC_DEBUG_DEBUG_RECT_HISTORY_H_