Web Inspector: [Resources] Only remember the tree element selection if explicitly made by user
https://bugs.webkit.org/show_bug.cgi?id=110105

Reviewed by Pavel Feldman.

This change instructs the Resources panel to remember the selected tree element only if it has been
selected by the user (not automatically, like selecting a parent when its child is removed).
All onselect() overrides pass the selectedByUser argument value
to BaseStorageTreeElement.prototype.onselect.
Drive-by: Use === comparisons everywhere.

* inspector/front-end/ResourcesPanel.js:
(WebInspector.ResourcesPanel.prototype._reset): Do not detach [immutable] category views.
(WebInspector.BaseStorageTreeElement.prototype.onselect): Remember itemURL on user gesture only.
(WebInspector.StorageCategoryTreeElement.prototype.onselect):
(WebInspector.FrameTreeElement.prototype.onselect):
(WebInspector.FrameResourceTreeElement.prototype.onselect):
(WebInspector.DatabaseTreeElement.prototype.onselect):
(WebInspector.DatabaseTableTreeElement.prototype.onselect):
(WebInspector.IDBDatabaseTreeElement.prototype.onselect):
(WebInspector.IDBObjectStoreTreeElement.prototype.onselect):
(WebInspector.IDBIndexTreeElement.prototype.onselect):
(WebInspector.DOMStorageTreeElement):
(WebInspector.DOMStorageTreeElement.prototype.onselect):
(WebInspector.CookieTreeElement.prototype.onselect):
(WebInspector.ApplicationCacheManifestTreeElement.prototype.onselect):
(WebInspector.ApplicationCacheFrameTreeElement.prototype.onselect):
(WebInspector.FileSystemTreeElement.prototype.onselect):
(WebInspector.FileSystemTreeElement.prototype.clear):
(WebInspector.ResourcesSearchController.prototype.nextSearchResult):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@143209 268f45cc-cd09-0410-ab3c-d52691b4dbfc