Remove ENABLE_MESSAGE_CENTER

ui/message_center/message_center_util.cc

Index: ui/message_center/message_center_util.cc
diff --git a/ui/message_center/message_center_util.cc b/ui/message_center/message_center_util.cc
index 916faa70b80c6f564155122d89c0e2e80d7f900e..913cf0d342f1c40ef883e5a5754760b449eed7b4 100644
--- a/ui/message_center/message_center_util.cc
+++ b/ui/message_center/message_center_util.cc
@@ -13,17 +13,23 @@ namespace message_center {
 // when a time period in Canary indicates the new notifications are acceptable
 // for default behavior.
 bool IsRichNotificationEnabled() {
+#if !defined(OS_WIN) && !defined(OS_MACOSX) && !defined(USE_ASH)
+  return false;
+#endif
+
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kDisableRichNotifications))
     return false;
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableRichNotifications))
     return true;
+
+// Not enabled by default on Mac yet.
 #if defined(OS_MACOSX)
   return false;
-#else
-  return true;
 #endif
+
+  return true;
 }
 
 }  // namespace message_center