https://bugs.webkit.org/show_bug.cgi?id=76693

Reviewed by Darin Adler.

Make ShadowRoot inherit DocumentFragment so that it matches the class hierarchy of IDL in the spec.
TreeScope becomes a separated class, which is now inherited by Document and ShadowRoot using multiple-inheritance.
This patch is pre-requirement for coming IDL change.

No tests. No change in behavior.

* dom/Document.cpp:
(WebCore::Document::Document):
(WebCore::Document::~Document):
(WebCore::Document::buildAccessKeyMap):
(WebCore::Document::childrenChanged):
(WebCore::Document::attach):
(WebCore::Document::detach):
* dom/Document.h:
(Document):
* dom/DocumentFragment.cpp:
(WebCore::DocumentFragment::DocumentFragment):
* dom/DocumentFragment.h:
(DocumentFragment):
* dom/DocumentOrderedMap.cpp:
(WebCore::DocumentOrderedMap::get):
* dom/ShadowRoot.cpp:
(WebCore::ShadowRoot::ShadowRoot):
(WebCore::ShadowRoot::~ShadowRoot):
(WebCore::ShadowRoot::attach):
* dom/ShadowRoot.h:
* dom/TreeScope.cpp:
(WebCore::TreeScope::TreeScope):
(WebCore::TreeScope::~TreeScope):
(WebCore::TreeScope::setParentTreeScope):
(WebCore::TreeScope::getImageMap):
(WebCore::TreeScope::findAnchor):
* dom/TreeScope.h:
(WebCore):
(WebCore::TreeScope::rootNode):
(TreeScope):
* dom/TreeScopeAdopter.cpp:
(WebCore::TreeScopeAdopter::moveTreeToNewScope):
* page/DragController.cpp:
(WebCore::asFileInput):
* page/FocusController.cpp:
(WebCore::ownerOfTreeScope):
(WebCore::FocusController::nextFocusableNode):
(WebCore::FocusController::previousFocusableNode):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@106530 268f45cc-cd09-0410-ab3c-d52691b4dbfc