cc: Do the math for a tile's content rect in layer space once.

cc/playback/display_list_raster_source.h

 // Copyright 2014 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_PLAYBACK_DISPLAY_LIST_RASTER_SOURCE_H_
 #define CC_PLAYBACK_DISPLAY_LIST_RASTER_SOURCE_H_
 
 #include <vector>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 23 matching lines @@
                               const gfx::Rect& canvas_rect,
                               float contents_scale) const override;
   void PerformSolidColorAnalysis(
       const gfx::Rect& content_rect,
       float contents_scale,
       RasterSource::SolidColorAnalysis* analysis) const override;
   bool IsSolidColor() const override;
   SkColor GetSolidColor() const override;
   gfx::Size GetSize() const override;
   void GatherPixelRefs(
-      const gfx::Rect& content_rect,
-      float contents_scale,
+      const gfx::Rect& layer_rect,
       std::vector<skia::PositionPixelRef>* pixel_refs) const override;
-  bool CoversRect(const gfx::Rect& content_rect,
-                  float contents_scale) const override;
+  bool CoversRect(const gfx::Rect& layer_rect) const override;
   bool HasRecordings() const override;
   void SetShouldAttemptToUseDistanceFieldText() override;
   bool ShouldAttemptToUseDistanceFieldText() const override;
   void DidBeginTracing() override;
   void AsValueInto(base::trace_event::TracedValue* array) const override;
   skia::RefPtr<SkPicture> GetFlattenedPicture() override;
   size_t GetPictureMemoryUsage() const override;
   bool CanUseLCDText() const override;
   scoped_refptr<RasterSource> CreateCloneWithoutLCDText() const override;
 
@@ skipping 34 matching lines @@
                     const gfx::Rect& canvas_bitmap_rect,
                     const gfx::Rect& canvas_playback_rect,
                     float contents_scale) const;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayListRasterSource);
 };
 
 }  // namespace cc
 
 #endif  // CC_PLAYBACK_DISPLAY_LIST_RASTER_SOURCE_H_