[Cleanup] Migrate the DriveMetricsProvider to use the Task Scheduler.

ios/chrome/browser/metrics/ios_chrome_metrics_service_client.mm

 // Copyright 2015 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 "ios/chrome/browser/metrics/ios_chrome_metrics_service_client.h"
 
 #include <stdint.h>
 
 #include <utility>
 #include <vector>
@@ skipping 205 matching lines @@
     stability_metrics_provider_ = stability_metrics_provider.get();
     metrics_service_->RegisterMetricsProvider(
         std::move(stability_metrics_provider));
   }
 
   metrics_service_->RegisterMetricsProvider(
       base::MakeUnique<metrics::ScreenInfoMetricsProvider>());
 
   {
     auto drive_metrics_provider =
-        base::MakeUnique<metrics::DriveMetricsProvider>(
-            web::WebThread::GetTaskRunnerForThread(web::WebThread::FILE),
-            ios::FILE_LOCAL_STATE);
+        base::MakeUnique<metrics::DriveMetricsProvider>(ios::FILE_LOCAL_STATE);
     drive_metrics_provider_ = drive_metrics_provider.get();
     metrics_service_->RegisterMetricsProvider(
         std::move(drive_metrics_provider));
   }
 
   {
     auto profiler_metrics_provider =
         base::MakeUnique<metrics::ProfilerMetricsProvider>(
             base::Bind(&metrics::IsCellularLogicEnabled));
     profiler_metrics_provider_ = profiler_metrics_provider.get();
@@ skipping 130 matching lines @@
     ukm_service_->Purge();
     ukm_service_->ResetClientId();
   }
   // Signal service manager to enable/disable UKM based on new state.
   UpdateRunningServices();
 }
 
 bool IOSChromeMetricsServiceClient::IsHistorySyncEnabledOnAllProfiles() {
   return SyncDisableObserver::IsHistorySyncEnabledOnAllProfiles();
 }