[SPv1] Always set a CompositorElementId on main graphics layers; use PaintLayer id.

third_party/WebKit/Source/core/page/scrolling/ScrollState.cpp

 // Copyright 2015 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 "core/page/scrolling/ScrollState.h"
 
 #include <memory>
 #include "core/dom/DOMNodeIds.h"
 #include "core/dom/Element.h"
 #include "core/dom/ExceptionCode.h"
+#include "core/layout/LayoutObject.h"
 #include "platform/graphics/CompositorElementId.h"
 #include "platform/wtf/PtrUtil.h"
 
 namespace blink {
 
 namespace {
 Element* ElementForId(int element_id) {
   Node* node = DOMNodeIds::NodeForId(element_id);
   DCHECK(node);
   if (!node)
@@ skipping 75 matching lines @@
   if (data_->current_native_scrolling_element() == CompositorElementId()) {
     element_.Clear();
     return nullptr;
   }
   return element_;
 }
 
 void ScrollState::SetCurrentNativeScrollingElement(Element* element) {
   element_ = element;
   data_->set_current_native_scrolling_element(CompositorElementIdFromDOMNodeId(
-      DOMNodeIds::IdForNode(element), CompositorElementIdNamespace::kScroll));
+      DOMNodeIds::IdForNode(element),
+      CompositorElementIdNamespace::kScrollState));
 }
 
 }  // namespace blink