[Metrics] Move MetricsServiceObserver into //components/metrics

chrome/browser/metrics/metrics_service_unittest.cc

 // Copyright (c) 2012 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/metrics/metrics_service.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/threading/platform_thread.h"
-#include "chrome/browser/metrics/metrics_service_observer.h"
 #include "chrome/browser/metrics/metrics_state_manager.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/scoped_testing_local_state.h"
 #include "chrome/test/base/testing_browser_process.h"
+#include "components/metrics/metrics_service_observer.h"
 #include "components/variations/metrics_util.h"
 #include "content/public/common/process_type.h"
 #include "content/public/common/webplugininfo.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/size.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/metrics/metrics_log_chromeos.h"
 #endif  // OS_CHROMEOS
@@ skipping 327 matching lines @@
 
   service.RemoveObserver(&observer1);
 
   service.OpenNewLog();
   EXPECT_EQ(2, observer1.observed());
   EXPECT_EQ(2, observer2.observed());
   service.log_manager_.FinishCurrentLog();
 
   service.RemoveObserver(&observer2);
 }