Allow MetricsProviders to request an initial stability log.

components/metrics.gypi

 # Copyright 2014 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': [
     {
       # GN version: //components/metrics
       'target_name': 'metrics',
       'type': 'static_library',
@@ skipping 19 matching lines @@
         'metrics/metrics_hashes.cc',
         'metrics/metrics_hashes.h',
         'metrics/metrics_log.cc',
         'metrics/metrics_log.h',
         'metrics/metrics_log_manager.cc',
         'metrics/metrics_log_manager.h',
         'metrics/metrics_log_uploader.cc',
         'metrics/metrics_log_uploader.h',
         'metrics/metrics_pref_names.cc',
         'metrics/metrics_pref_names.h',
+        'metrics/metrics_provider.cc',
         'metrics/metrics_provider.h',
         'metrics/metrics_reporting_scheduler.cc',
         'metrics/metrics_reporting_scheduler.h',
         'metrics/metrics_service.cc',
         'metrics/metrics_service.h',
         'metrics/metrics_service_client.h',
         'metrics/metrics_state_manager.cc',
         'metrics/metrics_state_manager.h',
         'metrics/metrics_switches.cc',
         'metrics/metrics_switches.h',
@@ skipping 87 matching lines @@
             'metrics/serialization/metric_sample.h',
           ],
           'dependencies': [
             '../base/base.gyp:base',
           ],
         },
       ],
     }],
   ],
 }