Main.activateWindow: always exit the overview if it's currently open

This way, clicking a message tray icon while the overview is open will
close the overview when activating its window.

Remove some other overview-related activation code which is now
redundant.

Also, remove calls to "global.get_current_time()" when calling
Main.activateWindow, since it's unnecessary (activateWindow will call
it itself if you don't pass in that arg).

https://bugzilla.gnome.org/show_bug.cgi?id=609765

js/ui/workspacesView.js

@@ -163,27 +163,13 @@ GenericWorkspacesView.prototype = {
         }
     },
 
-    /**
-     * activateWindowFromOverview:
-     * @metaWindow: A #MetaWindow
-     * @time: Integer even timestamp
-     *
-     * This function exits the overview, switching to the given @metaWindow.
-     * If an application filter is in effect, it will be cleared.
-     */
-    activateWindowFromOverview: function (metaWindow, time) {
-        if (this._windowSelectionAppId != null) {
-            this._clearApplicationWindowSelection(false);
-        }
-
-        Main.activateWindow(metaWindow, time);
-        Main.overview.hide();
-    },
-
     hide: function() {
         let activeWorkspaceIndex = global.screen.get_active_workspace_index();
         let activeWorkspace = this._workspaces[activeWorkspaceIndex];
 
+        if (this._windowSelectionAppId != null)
+            this._clearApplicationWindowSelection(false);
+
         activeWorkspace.actor.raise_top();
 
         for (let w = 0; w < this._workspaces.length; w++)