Move ElementAttributeData into Element.cpp/h

Move ElementAttributeData into Element.cpp/h
<http://webkit.org/b/109610>

Reviewed by Anders Carlsson.

Removed ElementAttributeData.cpp/h and moved the class itself into Element headquarters.
In the near future, Element should be the only client of this class, and thus it won't
be necessary for other classes to know anything about it.

* dom/ElementAttributeData.cpp: Removed.
* dom/ElementAttributeData.h: Removed.
* CMakeLists.txt:
* GNUmakefile.list.am:
* Target.pri:
* WebCore.gypi:
* WebCore.xcodeproj/project.pbxproj:
* dom/DOMAllInOne.cpp:
* dom/DocumentSharedObjectPool.cpp:
* dom/Element.cpp:
* dom/Element.h:
* workers/SharedWorker.cpp:
* Modules/webdatabase/DatabaseManager.cpp: Add ExceptionCode.h since Element.h doesn't pull it in anymore.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@142698 268f45cc-cd09-0410-ab3c-d52691b4dbfc