[Mac] Bring Chrome to the front when the settings button in a notification is clicked.

ui/message_center/cocoa/notification_controller.mm

 // Copyright (c) 2013 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 "ui/message_center/cocoa/notification_controller.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 672 matching lines @@
 
   return layoutParams.rootFrame;
 }
 
 - (void)close:(id)sender {
   [closeButton_ setTarget:nil];
   messageCenter_->RemoveNotification([self notificationID], /*by_user=*/true);
 }
 
 - (void)settingsClicked:(id)sender {
+  [NSApp activateIgnoringOtherApps:YES];
   messageCenter_->ClickOnSettingsButton([self notificationID]);
 }
 
 - (void)buttonClicked:(id)button {
   messageCenter_->ClickOnNotificationButton([self notificationID],
                                             [button tag]);
 }
 
 - (const message_center::Notification*)notification {
   return notification_;
@@ skipping 280 matching lines @@
                    forFont:(NSFont*)nsfont
           maxNumberOfLines:(size_t)lines {
   size_t unused;
   return [self wrapText:text
                 forFont:nsfont
        maxNumberOfLines:lines
             actualLines:&unused];
 }
 
 @end