[chromecast] ExternalMetrics has to destroy itself in file thread.

chromecast/browser/metrics/cast_metrics_service_client.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 "chromecast/browser/metrics/cast_metrics_service_client.h"
 
 #include "base/command_line.h"
 #include "base/guid.h"
 #include "base/i18n/rtl.h"
 #include "base/prefs/pref_service.h"
@@ skipping 157 matching lines @@
   }
 }
 
 CastMetricsServiceClient::CastMetricsServiceClient(
     base::TaskRunner* io_task_runner,
     PrefService* pref_service,
     net::URLRequestContextGetter* request_context)
     : io_task_runner_(io_task_runner),
       pref_service_(pref_service),
       cast_service_(NULL),
+      external_metrics_(NULL),
       metrics_service_loop_(base::MessageLoopProxy::current()),
       request_context_(request_context) {
 }
 
 CastMetricsServiceClient::~CastMetricsServiceClient() {
+  DCHECK(!external_metrics_);
 }
 
 void CastMetricsServiceClient::Initialize(CastService* cast_service) {
   DCHECK(cast_service);
   DCHECK(!cast_service_);
   cast_service_ = cast_service;
 
   metrics_state_manager_ = ::metrics::MetricsStateManager::Create(
       pref_service_,
       base::Bind(&CastMetricsServiceClient::IsReportingEnabled,
@@ skipping 40 matching lines @@
   // Reset clean_shutdown bit after InitializeMetricsRecordingState().
   metrics_service_->LogNeedForCleanShutdown();
 #endif  // !defined(OS_ANDROID)
 
   if (IsReportingEnabled())
     metrics_service_->Start();
 
   // Start external metrics collection, which feeds data from external
   // processes into the main external metrics.
 #if defined(OS_LINUX)
-  external_metrics_.reset(new ExternalMetrics(stability_provider));
+  external_metrics_ = new ExternalMetrics(stability_provider);
   external_metrics_->Start();
 #endif  // defined(OS_LINUX)
 }
 
 void CastMetricsServiceClient::Finalize() {
 #if !defined(OS_ANDROID)
   // Set clean_shutdown bit.
   metrics_service_->RecordCompletedSessionEnd();
 #endif  // !defined(OS_ANDROID)
+
+  // Stop metrics service cleanly before destructing CastMetricsServiceClient.
+#if defined(OS_LINUX)
+  external_metrics_->StopAndDestroy();
+  external_metrics_ = NULL;
+#endif  // defined(OS_LINUX)
+  metrics_service_->Stop();
 }
 
 bool CastMetricsServiceClient::IsReportingEnabled() {
   return PlatformIsReportingEnabled(cast_service_);
 }
 
 }  // namespace metrics
 }  // namespace chromecast