Dead code removal: remove MetricsResponse implementation and tests

chrome/chrome_browser.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
@@ skipping 1419 matching lines @@
         'browser/memory_purger.h',
         'browser/metrics/field_trial_synchronizer.cc',
         'browser/metrics/field_trial_synchronizer.h',
         'browser/metrics/metric_event_duration_details.h',
         'browser/metrics/metrics_log.cc',
         'browser/metrics/metrics_log.h',
         'browser/metrics/metrics_log_serializer.cc',
         'browser/metrics/metrics_log_serializer.h',
         'browser/metrics/metrics_reporting_scheduler.cc',
         'browser/metrics/metrics_reporting_scheduler.h',
-        'browser/metrics/metrics_response.cc',
-        'browser/metrics/metrics_response.h',
         'browser/metrics/metrics_service.cc',
         'browser/metrics/metrics_service.h',
         'browser/metrics/thread_watcher.cc',
         'browser/metrics/thread_watcher.h',
         'browser/metrics/tracking_synchronizer.cc',
         'browser/metrics/tracking_synchronizer.h',
         'browser/metrics/tracking_synchronizer_observer.h',
         'browser/metrics/variations_service.cc',
         'browser/metrics/variations_service.h',
         'browser/native_window_notification_source.h',
@@ skipping 4022 matching lines @@
           'variables': {
             'jni_gen_dir': 'chrome',
           },
           'includes': [ '../build/jni_generator.gypi' ],
         },
       ],
      },
     ],
   ],
 }