Add support for switching the audio output device for HTMLMediaElements.

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 "base/bind.h"
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/run_loop.h"
 #include "base/sync_socket.h"
 #include "content/browser/media/capture/audio_mirroring_manager.h"
@@ skipping 37 matching lines @@
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MockAudioMirroringManager);
 };
 
 class MockAudioRendererHost : public AudioRendererHost {
  public:
   MockAudioRendererHost(media::AudioManager* audio_manager,
                         AudioMirroringManager* mirroring_manager,
                         MediaInternals* media_internals,
-                        MediaStreamManager* media_stream_manager)
+                        MediaStreamManager* media_stream_manager,
+                        const ResourceContext::SaltCallback& salt_callback)
       : AudioRendererHost(kRenderProcessId,
                           audio_manager,
                           mirroring_manager,
                           media_internals,
-                          media_stream_manager),
+                          media_stream_manager,
+                          salt_callback),
         shared_memory_length_(0) {}
 
   // A list of mock methods.
   MOCK_METHOD2(OnStreamCreated, void(int stream_id, int length));
   MOCK_METHOD1(OnStreamPlaying, void(int stream_id));
   MOCK_METHOD1(OnStreamPaused, void(int stream_id));
   MOCK_METHOD1(OnStreamError, void(int stream_id));
 
  private:
   virtual ~MockAudioRendererHost() {
@@ skipping 59 matching lines @@
     }
   }
 
   scoped_ptr<base::SharedMemory> shared_memory_;
   scoped_ptr<base::SyncSocket> sync_socket_;
   uint32 shared_memory_length_;
 
   DISALLOW_COPY_AND_ASSIGN(MockAudioRendererHost);
 };
 
+namespace {
+  std::string ReturnMockSalt() {
+    return std::string();
+  }
+
+  ResourceContext::SaltCallback GetMockSaltCallback() {
+    return base::Bind(&ReturnMockSalt);
+  }
+}
+
 class AudioRendererHostTest : public testing::Test {
  public:
   AudioRendererHostTest() {
     audio_manager_.reset(media::AudioManager::CreateForTesting());
     base::CommandLine::ForCurrentProcess()->AppendSwitch(
         switches::kUseFakeDeviceForMediaStream);
     media_stream_manager_.reset(new MediaStreamManager(audio_manager_.get()));
     host_ = new MockAudioRendererHost(audio_manager_.get(),
                                       &mirroring_manager_,
                                       MediaInternals::GetInstance(),
-                                      media_stream_manager_.get());
+                                      media_stream_manager_.get(),
+                                      GetMockSaltCallback());
 
     // 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();
     SyncWithAudioThread();
@@ skipping 163 matching lines @@
   Create(false);
   Play();
   SimulateError();
   Close();
 }
 
 TEST_F(AudioRendererHostTest, CreateUnifiedStreamAndClose) {
   Create(true);
   Close();
 }
 

[miu, 2015/06/03 21:01:01]

Please add one or more unit tests for this new functionality.

 // TODO(hclam): Add tests for data conversation in low latency mode.
 
 }  // namespace content