Unify the calculation of main thread offset of sticky element

cc/blink/web_layer_impl.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/blink/web_layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 357 matching lines @@
   blink::WebLayerStickyPositionConstraint web_constraint;
   web_constraint.is_sticky = constraint.is_sticky;
   web_constraint.is_anchored_left = constraint.is_anchored_left;
   web_constraint.is_anchored_right = constraint.is_anchored_right;
   web_constraint.is_anchored_top = constraint.is_anchored_top;
   web_constraint.is_anchored_bottom = constraint.is_anchored_bottom;
   web_constraint.left_offset = constraint.left_offset;
   web_constraint.right_offset = constraint.right_offset;
   web_constraint.top_offset = constraint.top_offset;
   web_constraint.bottom_offset = constraint.bottom_offset;
-  web_constraint.parent_relative_sticky_box_offset =
-      constraint.parent_relative_sticky_box_offset;
   web_constraint.scroll_container_relative_sticky_box_rect =
       constraint.scroll_container_relative_sticky_box_rect;
   web_constraint.scroll_container_relative_containing_block_rect =
       constraint.scroll_container_relative_containing_block_rect;
   web_constraint.nearest_layer_shifting_sticky_box =
       constraint.nearest_layer_shifting_sticky_box;
   web_constraint.nearest_layer_shifting_containing_block =
       constraint.nearest_layer_shifting_containing_block;
   return web_constraint;
 }
 static cc::LayerStickyPositionConstraint ToStickyPositionConstraint(
     const blink::WebLayerStickyPositionConstraint& web_constraint) {
   cc::LayerStickyPositionConstraint constraint;
   constraint.is_sticky = web_constraint.is_sticky;
   constraint.is_anchored_left = web_constraint.is_anchored_left;
   constraint.is_anchored_right = web_constraint.is_anchored_right;
   constraint.is_anchored_top = web_constraint.is_anchored_top;
   constraint.is_anchored_bottom = web_constraint.is_anchored_bottom;
   constraint.left_offset = web_constraint.left_offset;
   constraint.right_offset = web_constraint.right_offset;
   constraint.top_offset = web_constraint.top_offset;
   constraint.bottom_offset = web_constraint.bottom_offset;
-  constraint.parent_relative_sticky_box_offset =
-      web_constraint.parent_relative_sticky_box_offset;
   constraint.scroll_container_relative_sticky_box_rect =
       web_constraint.scroll_container_relative_sticky_box_rect;
   constraint.scroll_container_relative_containing_block_rect =
       web_constraint.scroll_container_relative_containing_block_rect;
   constraint.nearest_layer_shifting_sticky_box =
       web_constraint.nearest_layer_shifting_sticky_box;
   constraint.nearest_layer_shifting_containing_block =
       web_constraint.nearest_layer_shifting_containing_block;
   return constraint;
 }
 void WebLayerImpl::SetStickyPositionConstraint(
     const blink::WebLayerStickyPositionConstraint& constraint) {
   layer_->SetStickyPositionConstraint(ToStickyPositionConstraint(constraint));
 }
 blink::WebLayerStickyPositionConstraint WebLayerImpl::StickyPositionConstraint()
     const {
   return ToWebLayerStickyPositionConstraint(
       layer_->sticky_position_constraint());
 }
 
+void WebLayerImpl::SetOffsetForStickyPosition(const blink::WebSize& offset) {
+  layer_->SetOffsetForStickyPositionFromMainThread(offset);
+}
+
+blink::WebSize WebLayerImpl::OffsetForStickyPosition() const {
+  return layer_->offset_for_sticky_position_from_main_thread();
+}
+
 void WebLayerImpl::SetScrollClient(blink::WebLayerScrollClient* scroll_client) {
   if (scroll_client) {
     layer_->set_did_scroll_callback(
         base::Bind(&blink::WebLayerScrollClient::DidScroll,
                    base::Unretained(scroll_client)));
   } else {
     layer_->set_did_scroll_callback(
         base::Callback<void(const gfx::ScrollOffset&)>());
   }
 }
@@ skipping 50 matching lines @@
 
 void WebLayerImpl::SetHasWillChangeTransformHint(bool has_will_change) {
   layer_->SetHasWillChangeTransformHint(has_will_change);
 }
 
 void WebLayerImpl::ShowScrollbars() {
   layer_->ShowScrollbars();
 }
 
 }  // namespace cc_blink