Raster PictureLayerTiling with fractional translation

cc/tiles/picture_layer_tiling.h

Index: cc/tiles/picture_layer_tiling.h
diff --git a/cc/tiles/picture_layer_tiling.h b/cc/tiles/picture_layer_tiling.h
index fcd06ace8cd20025ba207cfd4e22593ac392a40c..5362a071dcc2a243121ad13dcd205f6d4a26be86 100644
--- a/cc/tiles/picture_layer_tiling.h
+++ b/cc/tiles/picture_layer_tiling.h
@@ -17,6 +17,7 @@
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/region.h"
+#include "cc/base/scale_translate2d.h"
 #include "cc/base/tiling_data.h"
 #include "cc/tiles/tile.h"
 #include "cc/tiles/tile_priority.h"
@@ -81,7 +82,7 @@ class CC_EXPORT PictureLayerTiling {
   static const int kBorderTexels = 1;
 
   PictureLayerTiling(WhichTree tree,
-                     float contents_scale,
+                     const ScaleTranslate2d& contents_transform,
                      scoped_refptr<RasterSource> raster_source,
                      PictureLayerTilingClient* client);
   ~PictureLayerTiling();
@@ -118,7 +119,10 @@ class CC_EXPORT PictureLayerTiling {
   gfx::Size tiling_size() const { return tiling_data_.tiling_size(); }
   gfx::Rect live_tiles_rect() const { return live_tiles_rect_; }
   gfx::Size tile_size() const { return tiling_data_.max_texture_size(); }
-  float contents_scale() const { return contents_scale_; }
+  //  float contents_scale() const { return contents_scale_; }
+  const ScaleTranslate2d& contents_transform() const {
+    return contents_transform_;
+  }
   const TilingData* tiling_data() const { return &tiling_data_; }
 
   Tile* TileAt(int i, int j) const {
@@ -163,7 +167,7 @@ class CC_EXPORT PictureLayerTiling {
 
   void SetAllTilesOccludedForTesting() {
     gfx::Rect viewport_in_layer_space =
-        ScaleToEnclosingRect(current_visible_rect_, 1.0f / contents_scale_);
+        EnclosingLayerRectFromContentsRect(current_visible_rect_);
     current_occlusion_in_layer_space_ =
         Occlusion(gfx::Transform(),
                   SimpleEnclosedRegion(viewport_in_layer_space),
@@ -211,7 +215,7 @@ class CC_EXPORT PictureLayerTiling {
    private:
     const PictureLayerTiling* tiling_;
     gfx::Rect dest_rect_;
-    float dest_to_content_scale_;
+    ScaleTranslate2d dest_to_content_;
 
     Tile* current_tile_;
     gfx::Rect current_geometry_rect_;
@@ -319,8 +323,13 @@ class CC_EXPORT PictureLayerTiling {
   }
   void RemoveTilesInRegion(const Region& layer_region, bool recreate_tiles);
 
+  gfx::Rect EnclosingContentsRectFromLayerRect(
+      const gfx::Rect& layer_rect) const;
+  gfx::Rect EnclosingLayerRectFromContentsRect(
+      const gfx::Rect& contents_rect) const;
+
   // Given properties.
-  const float contents_scale_;
+  const ScaleTranslate2d contents_transform_;
   PictureLayerTilingClient* const client_;
   const WhichTree tree_;
   scoped_refptr<RasterSource> raster_source_;