Web Inspector: there should be a way to set HTML for given frame.

Web Inspector: there should be a way to set HTML for given frame.
https://bugs.webkit.org/show_bug.cgi?id=76548

Reviewed by Yury Semikhatsky.

* inspector/Inspector.json:
* inspector/InspectorPageAgent.cpp:
(WebCore::InspectorPageAgent::setDocumentContent):
* inspector/InspectorPageAgent.h:
* inspector/front-end/DOMAgent.js:
(WebInspector.DOMModelResourceBinding.prototype.setContent.callbackWrapper):
(WebInspector.DOMModelResourceBinding.prototype.setContent):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105288 268f45cc-cd09-0410-ab3c-d52691b4dbfc