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..bd293384f8940b21d22808b998a6c911d4ff436a 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -317,6 +317,9 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   gfx::ScrollOffset TotalScrollOffset() const {
     return ScrollOffsetWithDelta(scroll_offset(), ScrollDelta());
   }
+  gfx::Vector2dF MainScrollOffsetFracitionalPart() const {
+    return scroll_offset_fractional_part_;
+  }
 
   void SetDoubleSided(bool double_sided);
   bool double_sided() const { return double_sided_; }
@@ -636,6 +639,7 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   gfx::Size bounds_;
 
   gfx::ScrollOffset scroll_offset_;
+  gfx::Vector2dF scroll_offset_fractional_part_;
   // This variable indicates which ancestor layer (if any) whose size,
   // transformed relative to this layer, defines the maximum scroll offset for
   // this layer.