Web Inspector: create SourceFrames with content providers.

Web Inspector: create SourceFrames with content providers.
https://bugs.webkit.org/show_bug.cgi?id=86742

Reviewed by Vsevolod Vlasov.

Simple refactoring.

* inspector/front-end/JavaScriptSourceFrame.js:
(WebInspector.JavaScriptSourceFrame):
(WebInspector.JavaScriptSourceFrame.prototype.commitEditing):
(WebInspector.JavaScriptSourceFrame.prototype.afterTextChanged):
(WebInspector.JavaScriptSourceFrame.prototype._didEditContent):
* inspector/front-end/ResourceView.js:
(WebInspector.ResourceSourceFrame):
(WebInspector.ResourceSourceFrame.prototype.get resource):
* inspector/front-end/ScriptsPanel.js:
(WebInspector.ScriptsPanel.prototype._createSourceFrame):
* inspector/front-end/SourceFrame.js:
(WebInspector.SourceFrame):
(WebInspector.SourceFrame.prototype._ensureContentLoaded):
* inspector/front-end/StylesPanel.js:
(WebInspector.StyleSourceFrame):
* inspector/front-end/UISourceCode.js:
(WebInspector.UISourceCode.prototype.contentURL):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@117455 268f45cc-cd09-0410-ab3c-d52691b4dbfc