Convert scroll offsets to use SyncedProperty.

cc/layers/layer.cc

 // Copyright 2010 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.h"
 
 #include <algorithm>
 
 #include "base/atomic_sequence_num.h"
 #include "base/debug/trace_event.h"
@@ skipping 947 matching lines @@
       DCHECK_EQ((*it)->clip_parent(), this);
       LayerImpl* clip_child = layer->layer_tree_impl()->LayerById((*it)->id());
       DCHECK(clip_child);
       clip_children->insert(clip_child);
     }
     layer->SetClipChildren(clip_children);
   } else {
     layer->SetClipChildren(nullptr);
   }
 
-  // Adjust the scroll delta to be just the scrolls that have happened since
-  // the BeginMainFrame was sent.  This happens for impl-side painting
-  // in LayerImpl::ApplyScrollDeltasSinceBeginMainFrame in a separate tree walk.
-  if (layer->layer_tree_impl()->settings().impl_side_painting) {
-    layer->SetScrollOffset(scroll_offset_);
-  } else {
-    layer->SetScrollOffsetAndDelta(
-        scroll_offset_,
-        layer->ScrollDelta() - layer->sent_scroll_delta());
-    layer->SetSentScrollDelta(gfx::Vector2dF());
-  }
+  layer->PushScrollOffsetFromMainThread(scroll_offset_);
 
   // Wrap the copy_requests_ in a PostTask to the main thread.
   ScopedPtrVector<CopyOutputRequest> main_thread_copy_requests;
   for (ScopedPtrVector<CopyOutputRequest>::iterator it = copy_requests_.begin();
        it != copy_requests_.end();
        ++it) {
     scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner =
         layer_tree_host()->proxy()->MainThreadTaskRunner();
     scoped_ptr<CopyOutputRequest> original_request = copy_requests_.take(it);
     const CopyOutputRequest& original_request_ref = *original_request;
@@ skipping 22 matching lines @@
 
   // Reset any state that should be cleared for the next update.
   stacking_order_changed_ = false;
   update_rect_ = gfx::Rect();
 
   needs_push_properties_ = false;
   num_dependents_need_push_properties_ = 0;
 }
 
 scoped_ptr<LayerImpl> Layer::CreateLayerImpl(LayerTreeImpl* tree_impl) {
-  return LayerImpl::Create(tree_impl, layer_id_);
+  return LayerImpl::Create(tree_impl, layer_id_,
+                           new LayerImpl::SyncedScrollOffset);
 }
 
 bool Layer::DrawsContent() const {
   return draws_content_;
 }
 
 bool Layer::HasDrawableContent() const {
   return is_drawable_;
 }
 
@@ skipping 72 matching lines @@
 
 void Layer::ClearRenderSurface() {
   render_surface_ = nullptr;
 }
 
 void Layer::ClearRenderSurfaceLayerList() {
   if (render_surface_)
     render_surface_->ClearLayerLists();
 }
 
-gfx::ScrollOffset Layer::ScrollOffsetForAnimation() const {
-  return TotalScrollOffset();
+gfx::ScrollOffset Layer::ScrollOffsetForAnimation() {
+  return CurrentScrollOffset();
 }
 
 // On<Property>Animated is called due to an ongoing accelerated animation.
 // Since this animation is also being run on the compositor thread, there
 // is no need to request a commit to push this value over, so the value is
 // set directly rather than by calling Set<Property>.
 void Layer::OnFilterAnimated(const FilterOperations& filters) {
   filters_ = filters;
 }
 
@@ skipping 151 matching lines @@
     const TransformNode* node = tree.Node(transform_tree_index());
     gfx::Transform ssxform;
     tree.ComputeTransform(node->id, node->data.target_id, &ssxform);
     xform.ConcatTransform(ssxform);
   }
   xform.Scale(1.0 / contents_scale_x(), 1.0 / contents_scale_y());
   return xform;
 }
 
 }  // namespace cc