Revert of Fix overflow:overlay scrollbar width for paint.

third_party/WebKit/Source/platform/scroll/ScrollableArea.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * Copyright (C) 2008, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 617 matching lines @@
 int ScrollableArea::documentStep(ScrollbarOrientation orientation) const {
   return scrollSize(orientation);
 }
 
 float ScrollableArea::pixelStep(ScrollbarOrientation) const {
   return 1;
 }
 
 int ScrollableArea::verticalScrollbarWidth(
     OverlayScrollbarClipBehavior behavior) const {
-  DCHECK_EQ(behavior, IgnorePlatformOverlayScrollbarSize);
+  DCHECK_EQ(behavior, IgnoreOverlayScrollbarSize);
   if (Scrollbar* verticalBar = verticalScrollbar())
     return !verticalBar->isOverlayScrollbar() ? verticalBar->width() : 0;
   return 0;
 }
 
 int ScrollableArea::horizontalScrollbarHeight(
     OverlayScrollbarClipBehavior behavior) const {
-  DCHECK_EQ(behavior, IgnorePlatformOverlayScrollbarSize);
+  DCHECK_EQ(behavior, IgnoreOverlayScrollbarSize);
   if (Scrollbar* horizontalBar = horizontalScrollbar())
     return !horizontalBar->isOverlayScrollbar() ? horizontalBar->height() : 0;
   return 0;
 }
 
 FloatQuad ScrollableArea::localToVisibleContentQuad(const FloatQuad& quad,
                                                     const LayoutObject*,
                                                     unsigned) const {
   FloatQuad result(quad);
   result.move(-getScrollOffset());
@@ skipping 10 matching lines @@
                                         offset.y() - scrollOrigin().y());
   setScrollOffset(newOffset, CompositorScroll);
 }
 
 DEFINE_TRACE(ScrollableArea) {
   visitor->trace(m_scrollAnimator);
   visitor->trace(m_programmaticScrollAnimator);
 }
 
 }  // namespace blink