Fixes <https://bugs.webkit.org/show_bug.cgi?id=30337>.

Fixes <https://bugs.webkit.org/show_bug.cgi?id=30337>.
Web Inspector: Should be able to delete nodes from the Elements Tree.

Reviewed by Timothy Hatcher.

When the delete key is pressed and a element is selected in the tree,
the element should be deleted from the Elements Tree and the DOM.

* inspector/InspectorBackend.cpp:
(WebCore::InspectorBackend::removeNode):
* inspector/InspectorBackend.h:
* inspector/InspectorBackend.idl:
* inspector/InspectorFrontend.cpp:
(WebCore::InspectorFrontend::didRemoveNode):
* inspector/InspectorFrontend.h:
* inspector/front-end/ElementsPanel.js:
(WebInspector.ElementsPanel.prototype._updateModifiedNodes):
* inspector/front-end/ElementsTreeOutline.js:
(WebInspector.ElementsTreeOutline.prototype.handleKeyEvent):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@49505 268f45cc-cd09-0410-ab3c-d52691b4dbfc