Add histograms for data usage

chrome/browser/android/data_usage/external_data_use_observer.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/data_usage/external_data_use_observer.h"
 
 #include <utility>
 
 #include "base/containers/hash_tables.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 187 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!last_data_report_submitted_ticks_.is_null());
 
   if (success) {
     RecordDataUsageReportSubmission(DATAUSAGE_REPORT_SUBMISSION_SUCCESSFUL,
                                     pending_report_bytes_);
   } else {
     RecordDataUsageReportSubmission(DATAUSAGE_REPORT_SUBMISSION_FAILED,
                                     pending_report_bytes_);
   }
+  UMA_HISTOGRAM_TIMES(
+      "DataUsage.Perf.ReportSubmissionDuration",
+      base::TimeTicks::Now() - last_data_report_submitted_ticks_);
 
   last_data_report_submitted_ticks_ = base::TimeTicks();
   pending_report_bytes_ = 0;
 
   SubmitBufferedDataUseReport(false);
 }
 
 #if defined(OS_ANDROID)
 void ExternalDataUseObserver::OnApplicationStateChange(
     base::android::ApplicationState new_state) {
@@ skipping 220 matching lines @@
   size_t hash = 1;
   hash = hash * 23 + hash_function(k.label);
   hash = hash * 43 + k.connection_type;
   hash = hash * 83 + hash_function(k.mcc_mnc);
   return hash;
 }
 
 }  // namespace android
 
 }  // namespace chrome