Add compositor element id for scroll nodes in SPv2.

third_party/WebKit/Source/platform/graphics/compositing/PropertyTreeManager.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 "platform/graphics/compositing/PropertyTreeManager.h"
 
 #include "cc/layers/layer.h"
 #include "cc/trees/clip_node.h"
 #include "cc/trees/effect_node.h"
 #include "cc/trees/property_tree.h"
@@ skipping 116 matching lines @@
 
   m_effectStack.push_back(
       BlinkEffectAndCcIdPair{EffectPaintPropertyNode::root(), effectNode.id});
   m_rootLayer->SetEffectTreeIndex(effectNode.id);
 }
 
 void PropertyTreeManager::setupRootScrollNode() {
   cc::ScrollTree& scrollTree = m_propertyTrees.scroll_tree;
   scrollTree.clear();
   m_propertyTrees.layer_id_to_scroll_node_index.clear();
+  m_propertyTrees.element_id_to_scroll_node_index.clear();
   cc::ScrollNode& scrollNode =
       *scrollTree.Node(scrollTree.Insert(cc::ScrollNode(), kRealRootNodeId));
   DCHECK_EQ(scrollNode.id, kSecondaryRootNodeId);
   scrollNode.owning_layer_id = m_rootLayer->id();
   scrollNode.transform_id = kSecondaryRootNodeId;
   m_propertyTrees.layer_id_to_scroll_node_index[scrollNode.owning_layer_id] =
       scrollNode.id;
 
   m_scrollNodeMap.set(ScrollPaintPropertyNode::root(), scrollNode.id);
   m_rootLayer->SetScrollTreeIndex(scrollNode.id);
@@ skipping 113 matching lines @@
   compositorNode.bounds.SetSize(scrollNode->bounds().width(),
                                 scrollNode->bounds().height());
   compositorNode.user_scrollable_horizontal =
       scrollNode->userScrollableHorizontal();
   compositorNode.user_scrollable_vertical =
       scrollNode->userScrollableVertical();
   compositorNode.transform_id =
       ensureCompositorTransformNode(scrollNode->scrollOffsetTranslation());
   compositorNode.main_thread_scrolling_reasons =
       scrollNode->mainThreadScrollingReasons();
+  CompositorElementId compositorElementId = scrollNode->compositorElementId();
+  if (compositorElementId) {
+    compositorNode.element_id = compositorElementId;
+    m_propertyTrees.element_id_to_scroll_node_index[compositorElementId] = id;
+  }
 
   auto result = m_scrollNodeMap.set(scrollNode, id);
   DCHECK(result.isNewEntry);
   scrollTree().set_needs_update(true);
 
   return id;
 }
 
 void PropertyTreeManager::updateScrollOffset(int layerId, int scrollId) {
   cc::ScrollNode& scrollNode = *scrollTree().Node(scrollId);
@@ skipping 99 matching lines @@
   m_effectStack.push_back(BlinkEffectAndCcIdPair{nextEffect, effectNode.id});
 
   dummyLayer->set_property_tree_sequence_number(kPropertyTreeSequenceNumber);
   dummyLayer->SetTransformTreeIndex(kSecondaryRootNodeId);
   dummyLayer->SetClipTreeIndex(outputClipId);
   dummyLayer->SetEffectTreeIndex(effectNode.id);
   dummyLayer->SetScrollTreeIndex(kRealRootNodeId);
 }
 
 }  // namespace blink