Only scroll on main if the targeted frames need to scroll on main

third_party/WebKit/Source/core/page/Page.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All
  * Rights Reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 146 matching lines @@
              : ViewportDescription();
 }
 
 ScrollingCoordinator* Page::scrollingCoordinator() {
   if (!m_scrollingCoordinator && m_settings->acceleratedCompositingEnabled())
     m_scrollingCoordinator = ScrollingCoordinator::create(this);
 
   return m_scrollingCoordinator.get();
 }
 
-String Page::mainThreadScrollingReasonsAsText() {
-  if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
-    return scrollingCoordinator->mainThreadScrollingReasonsAsText();
-
-  return String();
-}
-
 ClientRectList* Page::nonFastScrollableRects(const LocalFrame* frame) {
   if (ScrollingCoordinator* scrollingCoordinator =
           this->scrollingCoordinator()) {
     // Hits in compositing/iframes/iframe-composited-scrolling.html
     DisableCompositingQueryAsserts disabler;
     scrollingCoordinator->updateAfterCompositingChangeIfNeeded();
   }
 
   if (!frame->view()->layerForScrolling())
     return ClientRectList::create();
@@ skipping 355 matching lines @@
     : chromeClient(nullptr),
       contextMenuClient(nullptr),
       editorClient(nullptr),
       spellCheckerClient(nullptr) {}
 
 Page::PageClients::~PageClients() {}
 
 template class CORE_TEMPLATE_EXPORT Supplement<Page>;
 
 }  // namespace blink