Raster PictureLayerTiling with fractional translation

cc/layers/picture_layer_impl.h

Index: cc/layers/picture_layer_impl.h
diff --git a/cc/layers/picture_layer_impl.h b/cc/layers/picture_layer_impl.h
index 9380b272600aff83d33eccc27dabb4a4dabf173c..c2b885664c2f766b33223a8ad6560c87b6b66255 100644
--- a/cc/layers/picture_layer_impl.h
+++ b/cc/layers/picture_layer_impl.h
@@ -39,6 +39,8 @@ class CC_EXPORT PictureLayerImpl
 
   Layer::LayerMaskType mask_type() const { return mask_type_; }
 
+  void ResetRasterScale();
+
   // LayerImpl overrides.
   const char* LayerTypeAsString() const override;
   std::unique_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
@@ -46,7 +48,8 @@ class CC_EXPORT PictureLayerImpl
   void AppendQuads(RenderPass* render_pass,
                    AppendQuadsData* append_quads_data) override;
   void NotifyTileStateChanged(const Tile* tile) override;
-  void ResetRasterScale();
+  SimpleEnclosedRegion VisibleOpaqueRegion() const override;
+
   void DidBeginTracing() override;
   void ReleaseResources() override;
   void ReleaseTileResources() override;
@@ -80,6 +83,8 @@ class CC_EXPORT PictureLayerImpl
 
   void SetNearestNeighbor(bool nearest_neighbor);
 
+  void SetUseTransformedRasterization(bool use);
+
   size_t GPUMemoryUsageInBytes() const override;
 
   void RunMicroBenchmark(MicroBenchmarkImpl* benchmark) override;
@@ -105,12 +110,13 @@ class CC_EXPORT PictureLayerImpl
   PictureLayerImpl(LayerTreeImpl* tree_impl,
                    int id,
                    Layer::LayerMaskType mask_type);
-  PictureLayerTiling* AddTiling(float contents_scale);
+  PictureLayerTiling* AddTiling(const ScaleTranslate2d& contents_transform);
   void RemoveAllTilings();
   void AddTilingsForRasterScale();
   void AddLowResolutionTilingIfNeeded();
   bool ShouldAdjustRasterScale() const;
   void RecalculateRasterScales();
+  gfx::Vector2dF CalculateRasterTranslation(float raster_scale);
   void CleanUpTilingsOnActiveLayer(
       const std::vector<PictureLayerTiling*>& used_tilings);
   float MinimumContentsScale() const;
@@ -151,6 +157,7 @@ class CC_EXPORT PictureLayerImpl
   const Layer::LayerMaskType mask_type_;
 
   bool nearest_neighbor_;
+  bool use_transformed_rasterization_;
   bool is_directly_composited_image_;
 
   // Use this instead of |visible_layer_rect()| for tiling calculations. This