Incrementally build main thread scrolling reasons [spv2]

third_party/WebKit/Source/platform/graphics/paint/ScrollPaintPropertyNode.cpp

 // Copyright 2016 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/paint/ScrollPaintPropertyNode.h"
 
 namespace blink {
 
 ScrollPaintPropertyNode* ScrollPaintPropertyNode::root() {
   DEFINE_STATIC_REF(ScrollPaintPropertyNode, root,
                     (ScrollPaintPropertyNode::create(
                         nullptr, TransformPaintPropertyNode::root(), IntSize(),
-                        IntSize(), false, false)));
+                        IntSize(), false, false, 0)));
   return root;
 }
 
 }  // namespace blink