Implement WebPushProvider.unregister() in Chromium.

content/browser/push_messaging/push_messaging_message_filter.h

Index: content/browser/push_messaging/push_messaging_message_filter.h
diff --git a/content/browser/push_messaging/push_messaging_message_filter.h b/content/browser/push_messaging/push_messaging_message_filter.h
index 942473968af72e68c9c6b6d52aca4fbf76e1614a..65ca7799137830e528619a2bf7df1198cf69db8f 100644
--- a/content/browser/push_messaging/push_messaging_message_filter.h
+++ b/content/browser/push_messaging/push_messaging_message_filter.h
@@ -82,6 +82,18 @@ class PushMessagingMessageFilter : public BrowserMessageFilter {
   void RegisterOnUI(const RegisterData& data,
                     const std::string& sender_id);
 
+
+  // Unregister methods --------------------------------------------------------
+
+  void OnUnregister(int request_id,
+                    int64 service_worker_registration_id);
+
+  void UnregisterOnUI(int request_id,
+                      int64 service_worker_registration_id,
+                      const GURL& requesting_origin);
+
+  void DidUnregister(int request_id, bool result);
+
   // TODO(mvanouwerkerk): Delete once the Push API flows through platform.
   // https://crbug.com/389194
   void DoPermissionStatusRequest(const GURL& requesting_origin,