Ensures that audio tasks cannot run after AudioManager is deleted.

content/browser/renderer_host/media/audio_renderer_host_unittest.cc

 // 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.
 
 #include "content/browser/renderer_host/media/audio_renderer_host.h"
 
 #include <stdint.h>
 
 #include <memory>
 
@@ skipping 239 matching lines @@
         kSalt);
 
     // Simulate IPC channel connected.
     host_->set_peer_process_for_testing(base::Process::Current());
   }
 
   ~AudioRendererHostTest() override {
     // Simulate closing the IPC channel and give the audio thread time to close
     // the underlying streams.
     host_->OnChannelClosing();
+    audio_manager_->GetTaskRunner()->PostTask(
+        FROM_HERE, base::Bind(&media::AudioManager::Shutdown,
+                              base::Unretained(audio_manager_.get())));
     SyncWithAudioThread();
-    // To correctly clean up the audio manager, we first put it in a
-    // ScopedAudioManagerPtr. It will immediately destruct, cleaning up the
-    // audio manager correctly.
-    media::ScopedAudioManagerPtr(audio_manager_.release());
 
     // Release the reference to the mock object.  The object will be destructed
     // on message_loop_.
     host_ = nullptr;
   }
 
  protected:
   void OverrideDevicePermissions(bool has_permissions) {
     host_->OverrideDevicePermissionsForTesting(has_permissions);
   }
@@ skipping 348 matching lines @@
 }
 
 TEST_F(AudioRendererHostTest, CreateFailsForInvalidRenderFrame) {
   CreateWithInvalidRenderFrameId();
   Close();
 }
 
 // TODO(hclam): Add tests for data conversation in low latency mode.
 
 }  // namespace content