Implement Element.scrollIntoView for scroll-behavior: smooth.

third_party/WebKit/Source/core/layout/LayoutObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 615 matching lines @@
   }
   // TODO(crbug.com/365897): we should get rid of detached layout subtrees, at
   // which point this code should not be reached.
   return nullptr;
 }
 
 bool LayoutObject::scrollRectToVisible(const LayoutRect& rect,
                                        const ScrollAlignment& alignX,
                                        const ScrollAlignment& alignY,
                                        ScrollType scrollType,
-                                       bool makeVisibleInVisualViewport) {
+                                       bool makeVisibleInVisualViewport,
+                                       ScrollBehavior scrollBehavior) {
   LayoutBox* enclosingBox = this->enclosingBox();
   if (!enclosingBox)
     return false;
 
   enclosingBox->scrollRectToVisible(rect, alignX, alignY, scrollType,
-                                    makeVisibleInVisualViewport);
+                                    makeVisibleInVisualViewport,
+                                    scrollBehavior);
   return true;
 }
 
 LayoutBox* LayoutObject::enclosingBox() const {
   LayoutObject* curr = const_cast<LayoutObject*>(this);
   while (curr) {
     if (curr->isBox())
       return toLayoutBox(curr);
     curr = curr->parent();
   }
@@ skipping 2869 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->parent())
       root = root->parent();
     root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif