Raster PictureLayerTiling with fractional translation

cc/tiles/tile.h

Index: cc/tiles/tile.h
diff --git a/cc/tiles/tile.h b/cc/tiles/tile.h
index 16d37d1491d88a5f9b7938eada47ed21ea32d2d2..954a4a7648e1d6d4eaf59895031e7a530d7fd5ab 100644
--- a/cc/tiles/tile.h
+++ b/cc/tiles/tile.h
@@ -10,6 +10,7 @@
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "cc/base/scale_translate2d.h"
 #include "cc/raster/tile_task.h"
 #include "cc/tiles/tile_draw_info.h"
 #include "ui/gfx/geometry/rect.h"
@@ -29,20 +30,20 @@ class CC_EXPORT Tile {
     int tiling_j_index;
     gfx::Rect enclosing_layer_rect;
     gfx::Rect content_rect;
-    float contents_scale;
+    ScaleTranslate2d raster_transform;
 
     CreateInfo(const PictureLayerTiling* tiling,
                int tiling_i_index,
                int tiling_j_index,
                const gfx::Rect& enclosing_layer_rect,
                const gfx::Rect& content_rect,
-               float contents_scale)
+               const ScaleTranslate2d& raster_transform)
         : tiling(tiling),
           tiling_i_index(tiling_i_index),
           tiling_j_index(tiling_j_index),
           enclosing_layer_rect(enclosing_layer_rect),
           content_rect(content_rect),
-          contents_scale(contents_scale) {}
+          raster_transform(raster_transform) {}
   };
 
   enum TileRasterFlags { USE_PICTURE_ANALYSIS = 1 << 0, IS_OPAQUE = 1 << 1 };
@@ -76,7 +77,8 @@ class CC_EXPORT Tile {
   const TileDrawInfo& draw_info() const { return draw_info_; }
   TileDrawInfo& draw_info() { return draw_info_; }
 
-  float contents_scale() const { return contents_scale_; }
+  float contents_scale_key() const { return raster_transform_.scale(); }
+  const ScaleTranslate2d& raster_transform() const { return raster_transform_; }
   const gfx::Rect& content_rect() const { return content_rect_; }
   const gfx::Rect& enclosing_layer_rect() const {
     return enclosing_layer_rect_;
@@ -132,7 +134,7 @@ class CC_EXPORT Tile {
   const PictureLayerTiling* tiling_;
   const gfx::Rect content_rect_;
   const gfx::Rect enclosing_layer_rect_;
-  const float contents_scale_;
+  const ScaleTranslate2d raster_transform_;
 
   TileDrawInfo draw_info_;