Add testing for subscription from service workers

content/child/push_messaging/push_provider.cc

Index: content/child/push_messaging/push_provider.cc
diff --git a/content/child/push_messaging/push_provider.cc b/content/child/push_messaging/push_provider.cc
index 254d855106bd9466a87c7009f3dff7f01609c275..91f0fafccd64a811f1e6cce7f355ef9d97e67b66 100644
--- a/content/child/push_messaging/push_provider.cc
+++ b/content/child/push_messaging/push_provider.cc
@@ -77,7 +77,8 @@ void PushProvider::subscribe(
       GetServiceWorkerRegistrationId(service_worker_registration);
   PushSubscriptionOptions content_options;
   content_options.user_visible_only = options.userVisibleOnly;
-  content_options.sender_info = options.applicationServerKey.utf8();
+
+  content_options.sender_info = options.applicationServerKey.latin1();

[Michael van Ouwerkerk, 2016/03/30 09:50:04]

Could you please document why this must be latin1 instead of utf8?

[harkness, 2016/03/30 10:51:49]

Done.

   thread_safe_sender_->Send(new PushMessagingHostMsg_SubscribeFromWorker(
       request_id, service_worker_registration_id, content_options));
 }