Reviewed by Yury Semikhatsky.

        Web Inspector: revision history storage is too slow.
        https://bugs.webkit.org/show_bug.cgi?id=59939

        It turns out that iterating localStorage keys is very
        expensive (results in slow inspector start), refactor revision
        history in order not to rely upon that operation.

        * inspector/front-end/Resource.js:
        (WebInspector.Resource):
        (WebInspector.Resource._resourceRevisionRegistry):
        (WebInspector.Resource.restoreRevisions.persist):
        (WebInspector.Resource.restoreRevisions):
        (WebInspector.Resource.persistRevision):
        (WebInspector.Resource.prototype._persistRevision):
        * inspector/front-end/ResourceTreeModel.js:
        (WebInspector.ResourceTreeModel.prototype._processCachedResources):
        (WebInspector.ResourceTreeModel.prototype._frameNavigated):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@85591 268f45cc-cd09-0410-ab3c-d52691b4dbfc