Add data usage tracking for GAIA auth api

google_apis/gaia/oauth2_api_call_flow.cc

Index: google_apis/gaia/oauth2_api_call_flow.cc
diff --git a/google_apis/gaia/oauth2_api_call_flow.cc b/google_apis/gaia/oauth2_api_call_flow.cc
index d5a674ff8f02f474521e4a3411ff9cf629a66ed9..e3d40f0e037e9c2a2164e764cb04bb56d758effe 100644
--- a/google_apis/gaia/oauth2_api_call_flow.cc
+++ b/google_apis/gaia/oauth2_api_call_flow.cc
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/strings/stringprintf.h"
+#include "google_apis/gaia/gaia_auth_util.h"
 #include "google_apis/gaia/gaia_urls.h"
 #include "net/base/escape.h"
 #include "net/base/load_flags.h"
@@ -81,6 +82,7 @@ std::unique_ptr<URLFetcher> OAuth2ApiCallFlow::CreateURLFetcher(
   std::unique_ptr<URLFetcher> result =
       net::URLFetcher::Create(0, CreateApiCallUrl(), request_type, this);
 
+  gaia::MarkURLFetcherAsGaia(result.get());
   result->SetRequestContext(context);
   result->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                        net::LOAD_DO_NOT_SAVE_COOKIES);