Undo scroll snaps in to_parent when NeedsSourceToParentUpdate.

cc/trees/property_tree_builder.cc

Index: cc/trees/property_tree_builder.cc
diff --git a/cc/trees/property_tree_builder.cc b/cc/trees/property_tree_builder.cc
index 12e2b7904542b69a72b4c939d1ce4625ec368a3e..6fdde22ff7e7b85316e55815e110dd539a18d11e 100644
--- a/cc/trees/property_tree_builder.cc
+++ b/cc/trees/property_tree_builder.cc
@@ -58,7 +58,6 @@ struct DataForRecursion {
   uint32_t main_thread_scrolling_reasons;
   bool scroll_tree_parent_created_by_uninheritable_criteria;
   const gfx::Transform* device_transform;
-  gfx::Vector2dF scroll_snap;
   gfx::Transform compound_transform_since_render_target;
   bool axis_align_since_render_target;
   SkColor safe_opaque_background_color;
@@ -540,7 +539,6 @@ bool AddTransformNodeIfNeeded(
                           ->offset_to_transform_parent();
       source_index =
           data_from_ancestor.transform_tree_parent->transform_tree_index();
-      source_offset -= data_from_ancestor.scroll_snap;
     }
   }
 
@@ -559,9 +557,6 @@ bool AddTransformNodeIfNeeded(
   }
   data_for_children->transform_tree_parent = layer;
 
-  if (IsContainerForFixedPositionLayers(layer) || is_fixed)
-    data_for_children->scroll_snap = gfx::Vector2dF();
-
   if (!requires_node) {
     data_for_children->should_flatten |= ShouldFlattenTransform(layer);
     gfx::Vector2dF local_offset = layer->position().OffsetFromOrigin() +
@@ -694,8 +689,6 @@ bool AddTransformNodeIfNeeded(
   // Flattening (if needed) will be handled by |node|.
   layer->set_should_flatten_transform_from_property_tree(false);
 
-  data_for_children->scroll_snap += node->scroll_snap;
-
   node->owner_id = layer->id();
 
   return true;