Web Inspector: Remove FrameContentView.js

Web Inspector: Remove FrameContentView.js
https://bugs.webkit.org/show_bug.cgi?id=144415

Reviewed by Joseph Pecoraro.

* UserInterface/Images/DOMTree.svg: Removed.
* UserInterface/Images/SourceCode.svg: Removed.
* UserInterface/Main.html: Removed FrameContentView.js.
* UserInterface/Views/FrameContentView.js: Removed.
* UserInterface/Views/PathComponentIcons.css:
(.source-code-icon .icon): Deleted.
(.dom-tree-icon .icon): Deleted.

* UserInterface/Views/ResourceSidebarPanel.js:
(WebInspector.ResourceSidebarPanel.prototype._mainFrameMainResourceDidChange.delayedWork):
(WebInspector.ResourceSidebarPanel.prototype._mainFrameMainResourceDidChange):
Simplify the code here. We don't need these checks now with tabs and the Storage tab.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@183671 268f45cc-cd09-0410-ab3c-d52691b4dbfc