Ensures that audio tasks cannot run after AudioManager is deleted.

content/browser/browser_main_loop.h

 // 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.
 
 #ifndef CONTENT_BROWSER_BROWSER_MAIN_LOOP_H_
 #define CONTENT_BROWSER_BROWSER_MAIN_LOOP_H_
 
 #include <memory>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
 #include "content/browser/browser_process_sub_thread.h"
 #include "content/public/browser/browser_main_runner.h"
-#include "media/audio/audio_manager.h"
 #include "services/resource_coordinator/memory/coordinator/coordinator_impl.h"
 
 #if defined(USE_AURA)
 namespace aura {
 class Env;
 }
 #endif
 
 namespace base {
 class CommandLine;
 class FilePath;
 class HighResolutionTimerManager;
 class MemoryPressureMonitor;
 class MessageLoop;
 class PowerMonitor;
 class SystemMonitor;
 namespace trace_event {
 class TraceEventSystemStatsMonitor;
 }  // namespace trace_event
 }  // namespace base
 
 namespace discardable_memory {
 class DiscardableSharedMemoryManager;
 }
 
 namespace media {
+class AudioManager;
 class AudioSystem;
 #if defined(OS_WIN)
 class SystemMessageWindowWin;
 #elif defined(OS_LINUX) && defined(USE_UDEV)
 class DeviceMonitorLinux;
 #endif
 class UserInputMonitor;
 #if defined(OS_MACOSX)
 class DeviceMonitorMac;
 #endif
@@ skipping 133 matching lines @@
 
   void MainMessageLoopRun();
 
   void InitializeMojo();
   base::FilePath GetStartupTraceFileName(
       const base::CommandLine& command_line) const;
   void InitStartupTracingForDuration(const base::CommandLine& command_line);
   void EndStartupTracing();
 
   void CreateAudioManager();
+  void DestroyAudioManager();
+
   bool UsingInProcessGpu() const;
 
   void InitializeMemoryManagementComponent();
 
   // Quick reference for initialization order:
   // Constructor
   // Init()
   // EarlyInitialization()
   // InitializeToolkit()
   // PreMainMessageLoopStart()
@@ skipping 81 matching lines @@
   std::unique_ptr<BrowserProcessSubThread> cache_thread_;
   std::unique_ptr<BrowserProcessSubThread> io_thread_;
 
   // Members initialized in |BrowserThreadsStarted()| --------------------------
   std::unique_ptr<base::Thread> indexed_db_thread_;
   std::unique_ptr<ServiceManagerContext> service_manager_context_;
   std::unique_ptr<mojo::edk::ScopedIPCSupport> mojo_ipc_support_;
 
   // |user_input_monitor_| has to outlive |audio_manager_|, so declared first.
   std::unique_ptr<media::UserInputMonitor> user_input_monitor_;
-  // AudioThread needs to outlive |audio_manager_|.
+  std::unique_ptr<media::AudioManager> audio_manager_;
+  // |audio_thread_| must be stopped before |audio_manager_| is deleted so
+  // that tasks referering to the |audio_manager_| cannot be posted.
   std::unique_ptr<AudioManagerThread> audio_thread_;
-  media::ScopedAudioManagerPtr audio_manager_;
   // Calls to |audio_system_| must not be posted to the audio thread if it
   // differs from the UI one.
   std::unique_ptr<media::AudioSystem> audio_system_;
 
   std::unique_ptr<midi::MidiService> midi_service_;
 
 #if defined(OS_WIN)
   std::unique_ptr<media::SystemMessageWindowWin> system_message_window_;
 #elif defined(OS_LINUX) && defined(USE_UDEV)
   std::unique_ptr<media::DeviceMonitorLinux> device_monitor_linux_;
@@ skipping 15 matching lines @@
       memory_instrumentation_coordinator_;
 
   // DO NOT add members here. Add them to the right categories above.
 
   DISALLOW_COPY_AND_ASSIGN(BrowserMainLoop);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BROWSER_MAIN_LOOP_H_