Reviewed by the Mitzpettel

        Before things get much more intertwined, move away from a global LocalStorage model
        to a per-PageGroup LocalStorage model.

        * page/DOMWindow.cpp:
        (WebCore::DOMWindow::localStorage): Get it from the current PageGroup, not the global
          LocalStorage (which doesn't exist anymore).

        * page/Page.cpp:
        * page/PageGroup.cpp:
        (WebCore::PageGroup::localStorage): Create a LocalStorage object on demand.
        * page/PageGroup.h:

        * storage/LocalStorage.cpp:
        (WebCore::LocalStorage::LocalStorage): Hold a back pointer to the owning PageGroup.
        (WebCore::LocalStorage::storageArea):
        * storage/LocalStorage.h:
        (WebCore::LocalStorage::create):

        * storage/LocalStorageArea.cpp:
        (WebCore::LocalStorageArea::LocalStorageArea): Hold a back pointer to the owning LocalStorage.
        * storage/LocalStorageArea.h:
        (WebCore::LocalStorageArea::create):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@32020 268f45cc-cd09-0410-ab3c-d52691b4dbfc