[GCM] Reset store on checkin rejection and add checkin state to internals

google_apis/gcm/engine/checkin_request.h

Index: google_apis/gcm/engine/checkin_request.h
diff --git a/google_apis/gcm/engine/checkin_request.h b/google_apis/gcm/engine/checkin_request.h
index 51bb17d2cef1eb5982761ce1e69b8a6df669790d..96e861c3c161e3d78e21f3aeffa6b1cee3b4c66c 100644
--- a/google_apis/gcm/engine/checkin_request.h
+++ b/google_apis/gcm/engine/checkin_request.h
@@ -17,6 +17,7 @@
 #include "google_apis/gcm/protocol/android_checkin.pb.h"
 #include "google_apis/gcm/protocol/checkin.pb.h"
 #include "net/base/backoff_entry.h"
+#include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "url/gurl.h"
 
@@ -36,8 +37,10 @@ class GCM_EXPORT CheckinRequest : public net::URLFetcherDelegate {
  public:
   // A callback function for the checkin request, accepting |checkin_response|
   // protobuf.
-  typedef base::Callback<void(const checkin_proto::AndroidCheckinResponse&
-                                  checkin_response)> CheckinRequestCallback;
+  typedef base::Callback<void(
+      net::HttpStatusCode response_code,
+      const checkin_proto::AndroidCheckinResponse& checkin_response)>
+      CheckinRequestCallback;
 
   // Checkin request details.
   struct GCM_EXPORT RequestInfo {