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

cc/playback/display_list_raster_source.cc

 // 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.
 
 #include "cc/playback/display_list_raster_source.h"
 
 #include "base/trace_event/trace_event.h"
 #include "cc/base/region.h"
 #include "cc/debug/debug_colors.h"
 #include "cc/playback/display_item_list.h"
@@ skipping 144 matching lines @@
   gfx::Rect layer_rect =
       gfx::ScaleToEnclosingRect(content_rect, 1.0f / contents_scale);
 
   layer_rect.Intersect(gfx::Rect(size_));
   skia::AnalysisCanvas canvas(layer_rect.width(), layer_rect.height());
   RasterForAnalysis(&canvas, layer_rect, 1.0f);
   analysis->is_solid_color = canvas.GetColorIfSolid(&analysis->solid_color);
 }
 
 void DisplayListRasterSource::GatherPixelRefs(
-    const gfx::Rect& content_rect,
-    float contents_scale,
+    const gfx::Rect& layer_rect,
     std::vector<skia::PositionPixelRef>* pixel_refs) const {
   DCHECK_EQ(0u, pixel_refs->size());
 
-  gfx::Rect layer_rect =
-      gfx::ScaleToEnclosingRect(content_rect, 1.0f / contents_scale);
-
   PixelRefMap::Iterator iterator(layer_rect, display_list_.get());
   while (iterator) {
     pixel_refs->push_back(*iterator);
     ++iterator;
   }
 }
 
-bool DisplayListRasterSource::CoversRect(const gfx::Rect& content_rect,
-                                         float contents_scale) const {
+bool DisplayListRasterSource::CoversRect(const gfx::Rect& layer_rect) const {
   if (size_.IsEmpty())
     return false;
-  gfx::Rect layer_rect =
-      gfx::ScaleToEnclosingRect(content_rect, 1.f / contents_scale);
-  layer_rect.Intersect(gfx::Rect(size_));
-
-  return recorded_viewport_.Contains(layer_rect);
+  gfx::Rect bounded_rect = layer_rect;
+  bounded_rect.Intersect(gfx::Rect(size_));
+  return recorded_viewport_.Contains(bounded_rect);
 }
 
 gfx::Size DisplayListRasterSource::GetSize() const {
   return size_;
 }
 
 bool DisplayListRasterSource::IsSolidColor() const {
   return is_solid_color_;
 }
 
@@ skipping 30 matching lines @@
 }
 
 scoped_refptr<RasterSource> DisplayListRasterSource::CreateCloneWithoutLCDText()
     const {
   bool can_use_lcd_text = false;
   return scoped_refptr<RasterSource>(
       new DisplayListRasterSource(this, can_use_lcd_text));
 }
 
 }  // namespace cc