Web Inspector: each node in a detached DOM tree is shown in its own "detached DOM tree" entry in heap profiler
https://bugs.webkit.org/show_bug.cgi?id=107819

Reviewed by Adam Barth.

Provide single RetainedDOMInfo for each group of DOM Node wrappers reported to GC.
Otherwise we have unequal RetainedDOMInfo groups for each wrapped node.

* bindings/v8/V8GCController.cpp:
(WebCore::ImplicitConnection::ImplicitConnection):
(WebCore::ImplicitConnection::retainedObjectInfo):
(ImplicitConnection):
(WebCore::WrapperGrouper::addObjectToGroup):
(WrapperGrouper):
(WebCore::WrapperGrouper::addNodeToGroup):
(WebCore::WrapperGrouper::apply):
(WebCore::V8GCController::opaqueRootForGC):
* bindings/v8/V8GCController.h:
(V8GCController):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@140949 268f45cc-cd09-0410-ab3c-d52691b4dbfc