Allow style sharing for canvas, iframe, embed and object.

third_party/WebKit/Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 3532 matching lines @@
     if (isUserActionElement())
         return false;
     if (!parentOrShadowHostElement()->childrenSupportStyleSharing())
         return false;
     if (this == document().cssTarget())
         return false;
     if (isHTMLElement() && toHTMLElement(this)->hasDirectionAuto())
         return false;
     if (hasAnimations())
         return false;
-    // Turn off style sharing for elements that can gain layers for reasons outside of the style system.
-    // See comments in LayoutObject::setStyle().
-    // FIXME: Why does gaining a layer from outside the style system require disabling sharing?
-    if (isHTMLFrameElementBase(*this) || isHTMLPlugInElement(*this) || isHTMLCanvasElement(*this))
-        return false;
     if (Fullscreen::isActiveFullScreenElement(*this))
         return false;
     return true;
 }
 
 DEFINE_TRACE(Element)
 {
 #if ENABLE(OILPAN)
     if (hasRareData())
         visitor->trace(elementRareData());
     visitor->trace(m_elementData);
 #endif
     ContainerNode::trace(visitor);
 }
 
 } // namespace blink