Implement Element.scrollIntoView for scroll-behavior: smooth.

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

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 87 matching lines @@
       m_lastMainThreadScrollingReasons(0) {}
 
 ScrollingCoordinator::~ScrollingCoordinator() {
   DCHECK(!m_page);
 }
 
 DEFINE_TRACE(ScrollingCoordinator) {
   visitor->trace(m_page);
   visitor->trace(m_horizontalScrollbars);
   visitor->trace(m_verticalScrollbars);
+  visitor->trace(m_programmaticScrollCoordinator);
 }
 
 void ScrollingCoordinator::setShouldHandleScrollGestureOnMainThreadRegion(
     const Region& region) {
   if (!m_page->mainFrame()->isLocalFrame() ||
       !m_page->deprecatedLocalMainFrame()->view())
     return;
   if (WebLayer* scrollLayer = toWebLayer(m_page->deprecatedLocalMainFrame()
                                              ->view()
                                              ->layoutViewportScrollableArea()
@@ skipping 1069 matching lines @@
   if (WebLayer* scrollLayer =
           frameView ? toWebLayer(frameView->layoutViewportScrollableArea()
                                      ->layerForScrolling())
                     : nullptr) {
     return WebSize(frameView->layoutViewportScrollableArea()->contentsSize()) !=
            scrollLayer->bounds();
   }
   return false;
 }
 
+ProgrammaticScrollCoordinator*
+ScrollingCoordinator::programmaticScrollCoordinator() {
+  if (!m_programmaticScrollCoordinator) {
+    m_programmaticScrollCoordinator = ProgrammaticScrollCoordinator::create();
+  }
+
+  return m_programmaticScrollCoordinator.get();
+}
+
 }  // namespace blink