Web Inspector: CPU pegged when inspecting LocalStorage that mutates.
https://bugs.webkit.org/show_bug.cgi?id=107937

Reviewed by Yury Semikhatsky.

The DOM storage agent will fire an event to the frontend based on the action
performed on the storage. Based on this action, the front-end will just add/update/remove
the entry in the view. This enhances the front-end responsiveness as the round trip
for fetching the storage entries has been eliminated.

Existing test: LayoutTests/inspector/storage-panel-dom-storage-update.html should verify the change

* inspector/Inspector.json:
* inspector/InspectorDOMStorageAgent.cpp:
(WebCore::InspectorDOMStorageAgent::didDispatchDOMStorageEvent):
* inspector/front-end/DOMStorage.js:
(WebInspector.DOMStorageModel.prototype._domStorageItemsCleared):
(WebInspector.DOMStorageModel.prototype._domStorageItemRemoved):
(WebInspector.DOMStorageModel.prototype._domStorageItemAdded):
(WebInspector.DOMStorageModel.prototype._domStorageItemUpdated):
(WebInspector.DOMStorageDispatcher.prototype.domStorageItemsCleared):
(WebInspector.DOMStorageDispatcher.prototype.domStorageItemRemoved):
(WebInspector.DOMStorageDispatcher.prototype.domStorageItemAdded):
(WebInspector.DOMStorageDispatcher.prototype.domStorageItemUpdated):
* inspector/front-end/DOMStorageItemsView.js:
(WebInspector.DOMStorageItemsView):
(WebInspector.DOMStorageItemsView.prototype.wasShown):
(WebInspector.DOMStorageItemsView.prototype._domStorageItemsCleared):
(WebInspector.DOMStorageItemsView.prototype._domStorageItemRemoved):
(WebInspector.DOMStorageItemsView.prototype._domStorageItemAdded):
(WebInspector.DOMStorageItemsView.prototype._domStorageItemUpdated):
(WebInspector.DOMStorageItemsView.prototype._update):
(WebInspector.DOMStorageItemsView.prototype._showDOMStorageEntries):
(WebInspector.DOMStorageItemsView.prototype._refreshButtonClicked):
(WebInspector.DOMStorageItemsView.prototype._editingCallback):
(WebInspector.DOMStorageItemsView.prototype._deleteCallback):
* inspector/front-end/ResourcesPanel.js:
(WebInspector.ResourcesPanel):
(WebInspector.ResourcesPanel.prototype._showDOMStorage.get if):
(WebInspector.ResourcesPanel.prototype._showDOMStorage):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142161 268f45cc-cd09-0410-ab3c-d52691b4dbfc