Add notification (and unit test) for closing prefs window so it can be cleane...

chrome/browser/cocoa/preferences_window_controller.mm

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/cocoa/preferences_window_controller.h"
 
 #include "base/mac_util.h"
 #include "chrome/common/pref_service.h"
 
-PreferencesWindowController* gPrefWindowSingleton = nil;
+NSString* const kUserDoneEditingPrefsNotification =
+    @"kUserDoneEditingPrefsNotification";
 
 @implementation PreferencesWindowController
 
 - (id)initWithPrefs:(PrefService*)prefs {
   DCHECK(prefs);
   // Use initWithWindowNibPath:: instead of initWithWindowNibName: so we
   // can override it in a unit test.
   NSString *nibpath = [mac_util::MainAppBundle()
                         pathForResource:@"Preferences"
                                  ofType:@"nib"];
@@ skipping 14 matching lines @@
 
 // Show the preferences window.
 - (IBAction)showPreferences:(id)sender {
   [self syncWithPrefs];
   [self showWindow:sender];
 }
 
 // Called when the window is being closed. Send out a notification that the
 // user is done editing preferences.
 - (void)windowWillClose:(NSNotification *)notification {
-  // TODO(pinkerton): send notification. Write unit test that makes sure
-  // we receive it.
+  [[NSNotificationCenter defaultCenter]
+      postNotificationName:kUserDoneEditingPrefsNotification
+                    object:self];
 }
 
 @end