Add a default implementation in metrics_default.cc of histograms methods in system_wrappers/interfac

webrtc/test/test_suite.cc

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/test/test_suite.h"
 
 #include "gflags/gflags.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "webrtc/base/logging.h"
+#include "webrtc/system_wrappers/include/metrics_default.h"
 #include "webrtc/test/testsupport/fileutils.h"
 #include "webrtc/test/testsupport/trace_to_stderr.h"
 #include "webrtc/test/field_trial.h"
 
 DEFINE_bool(logs, false, "print logs to stderr");
 
 DEFINE_string(force_fieldtrials, "",
     "Field trials control experimental feature code which can be forced. "
     "E.g. running with --force_fieldtrials=WebRTC-FooFeature/Enable/"
     " will assign the group Enable to field trial WebRTC-FooFeature.");
 
 namespace webrtc {
 namespace test {
 
 TestSuite::TestSuite(int argc, char** argv) {
   SetExecutablePath(argv[0]);
   testing::InitGoogleMock(&argc, argv);  // Runs InitGoogleTest() internally.
   // AllowCommandLineParsing allows us to ignore flags passed on to us by
   // Chromium build bots without having to explicitly disable them.
   google::AllowCommandLineReparsing();
   google::ParseCommandLineFlags(&argc, &argv, true);
 
   webrtc::test::InitFieldTrialsFromString(FLAGS_force_fieldtrials);
+  webrtc::metrics::Enable();
 }
 
 TestSuite::~TestSuite() {
 }
 
 int TestSuite::Run() {
   Initialize();
   int result = RUN_ALL_TESTS();
   Shutdown();
   return result;
 }
 
 void TestSuite::Initialize() {
   rtc::LogMessage::SetLogToStderr(FLAGS_logs);
   if (FLAGS_logs)
     trace_to_stderr_.reset(new TraceToStderr);
 }
 
 void TestSuite::Shutdown() {
 }
 
 }  // namespace test
 }  // namespace webrtc