[Metrics] Move MetricsServiceObserver into //components/metrics

chrome/chrome_browser.gypi

 # Copyright 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 1184 matching lines @@
         'browser/metrics/metric_event_duration_details.h',
         'browser/metrics/metrics_log.cc',
         'browser/metrics/metrics_log.h',
         'browser/metrics/metrics_log_chromeos.cc',
         'browser/metrics/metrics_log_chromeos.h',
         'browser/metrics/metrics_network_observer.cc',
         'browser/metrics/metrics_network_observer.h',
         'browser/metrics/metrics_reporting_scheduler.cc',
         'browser/metrics/metrics_reporting_scheduler.h',
         'browser/metrics/metrics_service_android.cc',
-        'browser/metrics/metrics_service_observer.cc',
-        'browser/metrics/metrics_service_observer.h',
         'browser/metrics/metrics_service.cc',
         'browser/metrics/metrics_service.h',
         'browser/metrics/metrics_services_manager.cc',
         'browser/metrics/metrics_services_manager.h',
         'browser/metrics/metrics_state_manager.cc',
         'browser/metrics/metrics_state_manager.h',
         'browser/metrics/perf_provider_chromeos.cc',
         'browser/metrics/perf_provider_chromeos.h',
         'browser/metrics/thread_watcher.cc',
         'browser/metrics/thread_watcher.h',
@@ skipping 2500 matching lines @@
             'package_name': 'org/chromium/chrome/browser',
             'template_deps': ['browser/android/tab_load_status.h'],
           },
           'includes': [ '../build/android/java_cpp_template.gypi' ],
         },
       ],
      },
     ],
   ],
 }