Start building message_center on Mac.

chrome/browser/notifications/notification_ui_manager_mac.mm

Index: chrome/browser/notifications/notification_ui_manager_mac.mm
diff --git a/chrome/browser/notifications/notification_ui_manager_mac.mm b/chrome/browser/notifications/notification_ui_manager_mac.mm
index 872d0bff4bdbe7998054147a88781d88e3086800..4921442903dda375702a1796a0e50215551edc09 100644
--- a/chrome/browser/notifications/notification_ui_manager_mac.mm
+++ b/chrome/browser/notifications/notification_ui_manager_mac.mm
@@ -10,6 +10,12 @@
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/balloon_notification_ui_manager.h"
 
+#if defined(ENABLE_MESSAGE_CENTER)
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/notifications/message_center_notification_manager.h"
+#include "ui/message_center/message_center_util.h"
+#endif
+
 @class NSUserNotificationCenter;
 
 // Since NSUserNotification and NSUserNotificationCenter are new classes in
@@ -94,6 +100,15 @@ NotificationUIManagerMac::ControllerNotification::~ControllerNotification() {
 
 // static
 NotificationUIManager* NotificationUIManager::Create(PrefService* local_state) {
+#if defined(ENABLE_MESSAGE_CENTER)
+  // TODO(rsesek): Remove this function and merge it with the one in
+  // notification_ui_manager.cc.
+  if (DelegatesToMessageCenter()) {
+    return new MessageCenterNotificationManager(
+        g_browser_process->message_center());
+  }
+#endif
+
   BalloonNotificationUIManager* balloon_manager = NULL;
   if (base::mac::IsOSMountainLionOrLater())
     balloon_manager = new NotificationUIManagerMac(local_state);