Add an override flag to enable metrics reporting.

components/metrics_services_manager/metrics_services_manager.cc

 // 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.
 
 #include "components/metrics_services_manager/metrics_services_manager.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "components/metrics/metrics_service.h"
@@ skipping 114 matching lines @@
   UpdateUkmService();
 
   GetRapporServiceImpl()->Update(may_record_, may_upload_);
 }
 
 void MetricsServicesManager::UpdateUkmService() {
   ukm::UkmService* ukm = GetUkmService();
   if (!ukm)
     return;
   bool sync_enabled =
+      client_->IsMetricsReportingForceEnabled() ||
       metrics_service_client_->IsHistorySyncEnabledOnAllProfiles();
   if (may_record_ && sync_enabled) {
     ukm->EnableRecording();
     if (may_upload_)
       ukm->EnableReporting();
     else
       ukm->DisableReporting();
   } else {
     ukm->DisableRecording();
     ukm->DisableReporting();
   }
 }
 
 void MetricsServicesManager::UpdateUploadPermissions(bool may_upload) {
-  UpdatePermissions(client_->IsMetricsReportingEnabled(), may_upload);
+  UpdatePermissions((client_->IsMetricsReportingForceEnabled() ||
+                     client_->IsMetricsReportingEnabled()),
+                    client_->IsMetricsReportingForceEnabled() || may_upload);
 }
 
 }  // namespace metrics_services_manager