GCM Engine: Split up reg/unreg UNKNOWN_ERROR to improve metrics

google_apis/gcm/engine/registration_request.h

Index: google_apis/gcm/engine/registration_request.h
diff --git a/google_apis/gcm/engine/registration_request.h b/google_apis/gcm/engine/registration_request.h
index cac838d5fa32bed2455578c6093bd2b03c8be118..1b5708ce79d5f45cf64bbc4a60cbcc9b0cc1a900 100644
--- a/google_apis/gcm/engine/registration_request.h
+++ b/google_apis/gcm/engine/registration_request.h
@@ -51,6 +51,10 @@ class GCM_EXPORT RegistrationRequest : public net::URLFetcherDelegate {
     HTTP_NOT_OK,                // HTTP status was not OK.
     NO_RESPONSE_BODY,           // No response body.
     REACHED_MAX_RETRIES,        // Reached maximum number of retries.
+    RESPONSE_PARSING_FAILED,    // Registration response parsing failed.
+    INTERNAL_SERVER_ERROR,      // Internal server error during request.
+    QUOTA_EXCEEDED,             // Registration quota exceeded.
+    TOO_MANY_REGISTRATIONS,     // Max registrations per device exceeded.
     // NOTE: always keep this entry at the end. Add new status types only
     // immediately above this line. Make sure to update the corresponding
     // histogram enum accordingly.