Add context menus to some entries

Use ShellEntry.addContextMenu() to add context menus to most
existing entries, with the exception of:

 - the login dialog - it may act be used to enter either the
                      username (e.g. no password entry) or the
                      password, and copy/paste does not make sense
                      (nowhere to copy from, nowhere to paste to)
 - notifications    - while adding a context menu is useful here as
                      well, it will require changes to the tray's
                      focus grab handling, so leave those entries
                      out for now

https://bugzilla.gnome.org/show_bug.cgi?id=659275

js/ui/lookingGlass.js

@@ -17,6 +17,7 @@ const Mainloop = imports.mainloop;
 const History = imports.misc.history;
 const ExtensionSystem = imports.ui.extensionSystem;
 const Link = imports.ui.link;
+const ShellEntry = imports.ui.shellEntry;
 const Tweener = imports.ui.tweener;
 const Main = imports.ui.main;
 
@@ -816,6 +817,7 @@ LookingGlass.prototype = {
         entryArea.add(label);
 
         this._entry = new St.Entry({ can_focus: true });
+        ShellEntry.addContextMenu(this._entry);
         entryArea.add(this._entry, { expand: true });
 
         this._windowList = new WindowList();