cc: Impl thread scroll on ScrollNode instead of LayerImpl

cc/layers/layer_impl.cc

 // Copyright 2012 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/layers/layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <utility>
@@ skipping 189 matching lines @@
       scroll_state->delta_consumed_for_scroll_sequence() &&
       scroll_state->current_native_scrolling_node()->owner_id != id()) {
     return;
   }
 
   ApplyScroll(scroll_state);
 }
 
 void LayerImpl::ApplyScroll(ScrollState* scroll_state) {
   DCHECK(scroll_state);
-  layer_tree_impl()->ApplyScroll(this, scroll_state);
+  ScrollNode* node = layer_tree_impl()->property_trees()->scroll_tree.Node(
+      scroll_tree_index());
+  layer_tree_impl()->ApplyScroll(node, scroll_state);
 }
 
 void LayerImpl::SetNumDescendantsThatDrawContent(int num_descendants) {
   if (num_descendants_that_draw_content_ == num_descendants)
     return;
   num_descendants_that_draw_content_ = num_descendants;
   SetNeedsPushProperties();
 }
 
 void LayerImpl::SetClipParent(LayerImpl* ancestor) {
@@ skipping 199 matching lines @@
   }
 }
 
 void LayerImpl::GetContentsResourceId(ResourceId* resource_id,
                                       gfx::Size* resource_size) const {
   NOTREACHED();
   *resource_id = 0;
 }
 
 gfx::Vector2dF LayerImpl::ScrollBy(const gfx::Vector2dF& scroll) {
-  gfx::ScrollOffset adjusted_scroll(scroll);
-  if (!user_scrollable_horizontal_)
-    adjusted_scroll.set_x(0);
-  if (!user_scrollable_vertical_)
-    adjusted_scroll.set_y(0);
-  DCHECK(scrollable());
-  gfx::ScrollOffset old_offset = CurrentScrollOffset();
-  gfx::ScrollOffset new_offset =
-      ClampScrollOffsetToLimits(old_offset + adjusted_scroll);
-  SetCurrentScrollOffset(new_offset);
-
-  gfx::ScrollOffset unscrolled =
-      old_offset + gfx::ScrollOffset(scroll) - new_offset;
-  return gfx::Vector2dF(unscrolled.x(), unscrolled.y());
+  ScrollTree& scroll_tree = layer_tree_impl()->property_trees()->scroll_tree;
+  ScrollNode* scroll_node = scroll_tree.Node(scroll_tree_index());
+  return scroll_tree.ScrollBy(scroll_node, scroll, layer_tree_impl());
 }
 
 void LayerImpl::SetScrollClipLayer(int scroll_clip_layer_id) {
   if (scroll_clip_layer_id_ == scroll_clip_layer_id)
     return;
 
   layer_tree_impl()->UnregisterScrollLayer(this);
   scroll_clip_layer_id_ = scroll_clip_layer_id;
   layer_tree_impl()->RegisterScrollLayer(this);
 }
 
 LayerImpl* LayerImpl::scroll_clip_layer() const {
   return layer_tree_impl()->LayerById(scroll_clip_layer_id_);
 }
 
 bool LayerImpl::scrollable() const {
   return scroll_clip_layer_id_ != Layer::INVALID_ID;
 }
 
+void LayerImpl::set_user_scrollable_horizontal(bool scrollable) {
+  user_scrollable_horizontal_ = scrollable;
+}
+
+void LayerImpl::set_user_scrollable_vertical(bool scrollable) {
+  user_scrollable_vertical_ = scrollable;
+}
+
 bool LayerImpl::user_scrollable(ScrollbarOrientation orientation) const {
   return (orientation == HORIZONTAL) ? user_scrollable_horizontal_
                                      : user_scrollable_vertical_;
 }
 
 skia::RefPtr<SkPicture> LayerImpl::GetPicture() {
   return skia::RefPtr<SkPicture>();
 }
 
 scoped_ptr<LayerImpl> LayerImpl::CreateLayerImpl(LayerTreeImpl* tree_impl) {
@@ skipping 1108 matching lines @@
            .layer_transforms_should_scale_layer_contents) {
     return default_scale;
   }
 
   gfx::Vector2dF transform_scales = MathUtil::ComputeTransform2dScaleComponents(
       DrawTransform(), default_scale);
   return std::max(transform_scales.x(), transform_scales.y());
 }
 
 }  // namespace cc