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

cc/trees/occlusion_tracker.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_TREES_OCCLUSION_TRACKER_H_
 #define CC_TREES_OCCLUSION_TRACKER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 14 matching lines @@
 // class is called to notify it about the current target surface. Then,
 // occlusion in the content space of the current layer may be queried, via
 // methods such as Occluded() and UnoccludedContentRect(). If the current layer
 // owns a RenderSurfaceImpl, then occlusion on that RenderSurfaceImpl may also
 // be queried via surfaceOccluded() and surfaceUnoccludedContentRect(). Finally,
 // once finished with the layer, occlusion behind the layer should be marked by
 // calling MarkOccludedBehindLayer().
 template <typename LayerType, typename RenderSurfaceType>
 class CC_EXPORT OcclusionTrackerBase {
  public:
-  OcclusionTrackerBase(gfx::Rect screen_space_clip_rect,
+  OcclusionTrackerBase(const gfx::Rect& screen_space_clip_rect,
                        bool record_metrics_for_frame);
   ~OcclusionTrackerBase();
 
   // Called at the beginning of each step in the LayerIterator's front-to-back
   // traversal.
   void EnterLayer(const LayerIteratorPosition<LayerType>& layer_iterator);
   // Called at the end of each step in the LayerIterator's front-to-back
   // traversal.
   void LeaveLayer(const LayerIteratorPosition<LayerType>& layer_iterator);
 
   // Returns true if the given rect in content space for a layer is fully
   // occluded in either screen space or the layer's target surface.
   // |render_target| is the contributing layer's render target, and
   // |draw_transform| and |impl_draw_transform_is_unknown| are relative to that.
   bool Occluded(const LayerType* render_target,
-                gfx::Rect content_rect,
+                const gfx::Rect& content_rect,
                 const gfx::Transform& draw_transform,
                 bool impl_draw_transform_is_unknown) const;
 
   // Gives an unoccluded sub-rect of |content_rect| in the content space of a
   // layer. Used when considering occlusion for a layer that paints/draws
   // something. |render_target| is the contributing layer's render target, and
   // |draw_transform| and |impl_draw_transform_is_unknown| are relative to that.
   gfx::Rect UnoccludedContentRect(
       const LayerType* render_target,
-      gfx::Rect content_rect,
+      const gfx::Rect& content_rect,
       const gfx::Transform& draw_transform,
       bool impl_draw_transform_is_unknown) const;
 
   // Gives an unoccluded sub-rect of |content_rect| in the content space of the
   // render_target owned by the layer. Used when considering occlusion for a
   // contributing surface that is rendering into another target.
   gfx::Rect UnoccludedContributingSurfaceContentRect(
       const LayerType* layer,
       bool for_replica,
-      gfx::Rect content_rect) const;
+      const gfx::Rect& content_rect) const;
 
   // Report operations for recording overdraw metrics.
   OverdrawMetrics* overdraw_metrics() const {
     return overdraw_metrics_.get();
   }
 
   // Gives the region of the screen that is not occluded by something opaque.
   Region ComputeVisibleRegionInScreen() const {
     DCHECK(!stack_.back().target->parent());
     return SubtractRegions(screen_space_clip_rect_,
@@ skipping 73 matching lines @@
 typedef OcclusionTrackerBase<Layer, RenderSurface> OcclusionTracker;
 typedef OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl> OcclusionTrackerImpl;
 #if !defined(COMPILER_MSVC)
 extern template class OcclusionTrackerBase<Layer, RenderSurface>;
 extern template class OcclusionTrackerBase<LayerImpl, RenderSurfaceImpl>;
 #endif
 
 }  // namespace cc
 
 #endif  // CC_TREES_OCCLUSION_TRACKER_H_