cleanup: Use EventRouter instead of ExtensionSystem::Get->event_router()

chrome/browser/extensions/extension_messages_apitest.cc

Index: chrome/browser/extensions/extension_messages_apitest.cc
diff --git a/chrome/browser/extensions/extension_messages_apitest.cc b/chrome/browser/extensions/extension_messages_apitest.cc
index 047e232720744da19f196e143566c6d9f7143bdb..cc1417486e4781737b82e4939b9b65d8c162c554 100644
--- a/chrome/browser/extensions/extension_messages_apitest.cc
+++ b/chrome/browser/extensions/extension_messages_apitest.cc
@@ -72,8 +72,8 @@ class MessageSender : public content::NotificationObserver {
   virtual void Observe(int type,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE {
-    EventRouter* event_router = ExtensionSystem::Get(
-        content::Source<Profile>(source).ptr())->event_router();
+    EventRouter* event_router =
+        EventRouter::Get(content::Source<Profile>(source).ptr());
 
     // Sends four messages to the extension. All but the third message sent
     // from the origin http://b.com/ are supposed to arrive.