signin: record http response codes and net errors in OAuth2AccessTokenFetcher.

google_apis/gaia/oauth2_access_token_fetcher.h

Index: google_apis/gaia/oauth2_access_token_fetcher.h
diff --git a/google_apis/gaia/oauth2_access_token_fetcher.h b/google_apis/gaia/oauth2_access_token_fetcher.h
index 11ac6ea8b5c702a9611802b444444fdf7c80cce4..90805c0996353a28d5c118e1403ec6071946c657 100644
--- a/google_apis/gaia/oauth2_access_token_fetcher.h
+++ b/google_apis/gaia/oauth2_access_token_fetcher.h
@@ -90,9 +90,15 @@ class OAuth2AccessTokenFetcher : public net::URLFetcherDelegate {
       const std::string& client_secret,
       const std::string& refresh_token,
       const std::vector<std::string>& scopes);
-  static bool ParseGetAccessTokenResponse(const net::URLFetcher* source,
-                                          std::string* access_token,
-                                          int* expires_in);
+
+  static bool ParseGetAccessTokenSuccessResponse(
+      const net::URLFetcher* source,
+      std::string* access_token,
+      int* expires_in);
+
+  static bool ParseGetAccessTokenFailureResponse(
+      const net::URLFetcher* source,
+      std::string* error);
 
   // State that is set during construction.
   OAuth2AccessTokenConsumer* const consumer_;