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

cc/playback/display_list_raster_source.h

Index: cc/playback/display_list_raster_source.h
diff --git a/cc/playback/display_list_raster_source.h b/cc/playback/display_list_raster_source.h
index 9823d96b123611ae0d99255da1a3afe43e49955f..6f8561f1f14e8556fbaf2ed93eaf724b1753679a 100644
--- a/cc/playback/display_list_raster_source.h
+++ b/cc/playback/display_list_raster_source.h
@@ -41,11 +41,9 @@ class CC_EXPORT DisplayListRasterSource : public RasterSource {
   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;