Add data usage tracking for GAIA auth api and GCM engine service

google_apis/gcm/engine/checkin_request.cc

Index: google_apis/gcm/engine/checkin_request.cc
diff --git a/google_apis/gcm/engine/checkin_request.cc b/google_apis/gcm/engine/checkin_request.cc
index ad13923d72ece93221bd561bf5f1f6e92c6d766f..0839c4e83bc1aabc8159ad1c9aa7c59365a9a081 100644
--- a/google_apis/gcm/engine/checkin_request.cc
+++ b/google_apis/gcm/engine/checkin_request.cc
@@ -8,6 +8,7 @@
 #include "base/location.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/threading/thread_task_runner_handle.h"
+#include "components/data_use_measurement/core/data_use_user_data.h"
 #include "google_apis/gcm/monitoring/gcm_stats_recorder.h"
 #include "google_apis/gcm/protocol/checkin.pb.h"
 #include "net/base/load_flags.h"
@@ -151,6 +152,8 @@ void CheckinRequest::Start() {
   url_fetcher_->SetUploadData(kRequestContentType, upload_data);
   url_fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SEND_COOKIES |
                              net::LOAD_DO_NOT_SAVE_COOKIES);
+  data_use_measurement::DataUseUserData::AttachToFetcher(
+      request_.get(), data_use_measurement::DataUseUserData::GCM_ENGINE);
   recorder_->RecordCheckinInitiated(request_info_.android_id);
   request_start_time_ = base::TimeTicks::Now();
   url_fetcher_->Start();