Ensures that audio tasks cannot run after AudioManager is deleted.

content/browser/renderer_host/media/media_devices_dispatcher_host_unittest.cc

 // Copyright 2016 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 "content/browser/renderer_host/media/media_devices_dispatcher_host.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <queue>
@@ skipping 269 matching lines @@
   }
 
   // The order of these members is important on teardown:
   // MediaDevicesDispatcherHost expects to be destroyed on the IO thread while
   // MediaStreamManager expects to be destroyed after the IO thread has been
   // uninitialized.
   std::unique_ptr<MediaStreamManager> media_stream_manager_;
   content::TestBrowserThreadBundle thread_bundle_;
   std::unique_ptr<MediaDevicesDispatcherHost> host_;
 
-  std::unique_ptr<media::AudioManager, media::AudioManagerDeleter>
-      audio_manager_;
+  std::unique_ptr<media::AudioManager> audio_manager_;
   std::unique_ptr<media::AudioSystem> audio_system_;
   content::TestBrowserContext browser_context_;
   MediaDeviceEnumeration physical_devices_;
   url::Origin origin_;
 
   std::vector<MediaDeviceInfoArray> enumerated_devices_;
 };
 
 TEST_F(MediaDevicesDispatcherHostTest, EnumerateAudioInputDevices) {
   EnumerateDevicesAndWaitForResult(true, false, false);
@@ skipping 80 matching lines @@
   // On Windows, the underlying MediaStreamManager uses a separate thread for
   // video capture which must be flushed to guarantee that the callback bound to
   // GetVIdeoInputCapabilities above is invoked before the end of this test's
   // body.
   media_stream_manager_->FlushVideoCaptureThreadForTesting();
   base::RunLoop().RunUntilIdle();
 #endif
 }
 
 };  // namespace content