Fixed position layer counter-scroll with main thread scroll offset fractional part

cc/layers/layer.h

Index: cc/layers/layer.h
diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index e4344127c7643976dff8a2231d7ad44438bf0d1c..ddaaac5e77c67d7fcf9d17265d9a7b4f7e29ba07 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -266,6 +266,10 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
 
   RenderSurface* render_surface() const { return render_surface_.get(); }
   void SetScrollOffset(const gfx::ScrollOffset& scroll_offset);
+  void SetScrollOffsetFractionalPart(
+      const gfx::Vector2dF& scroll_offset_fractional_part);
+  gfx::Vector2dF MainScrollOffsetFractionalPart() const;
+
   gfx::ScrollOffset scroll_offset() const { return scroll_offset_; }
   void SetScrollOffsetFromImplSide(const gfx::ScrollOffset& scroll_offset);