6% regression in intl1 page cycler on chromium-mac
https://bugs.webkit.org/show_bug.cgi?id=110784

Reviewed by Eric Seidel.

This patch reverts http://trac.webkit.org/changeset/143014 to see if
that's the cause of the PLT regression. If it's not the cause, I'll
roll it back in.

* dom/Element.cpp:
(WebCore::Element::addAttributeInternal):
(WebCore::ShareableElementData::ShareableElementData):
(WebCore::UniqueElementData::makeShareableCopy):
(WebCore::ElementData::addAttribute):
(WebCore::ElementData::removeAttribute):
(WebCore::ElementData::reportMemoryUsage):
* dom/Element.h:
(ElementData):
(UniqueElementData):
(WebCore::ElementData::mutableAttributeVector):
(WebCore):
(WebCore::ElementData::immutableAttributeArray):
(WebCore::ElementData::length):
(WebCore::ElementData::getAttributeItem):
(WebCore::ElementData::attributeItem):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@143983 268f45cc-cd09-0410-ab3c-d52691b4dbfc