Enable renderer side mixing behind a flag.

content/renderer/media/audio_renderer_mixer_manager_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/memory/scoped_ptr.h"
+#include "content/renderer/media/audio_device_factory.h"
+#include "content/renderer/media/audio_renderer_mixer_manager.h"
+#include "media/base/audio_renderer_mixer.h"
+#include "media/base/audio_renderer_mixer_input.h"
+#include "media/base/fake_audio_render_callback.h"
+#include "media/base/mock_audio_renderer_sink.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+static const int kBitsPerChannel = 16;
+static const int kSampleRate = 48000;
+static const int kBufferSize = 8192;
+static const ChannelLayout kChannelLayout = CHANNEL_LAYOUT_STEREO;
+
+// By sub-classing content::AudioDeviceFactory we've overridden the factory to
+// use our CreateAudioDevice() method globally.
+class MockAudioRenderSinkFactory : public content::AudioDeviceFactory {
+  virtual media::MockAudioRendererSink* CreateAudioDevice() {
+    media::MockAudioRendererSink* sink = new media::MockAudioRendererSink();
+    EXPECT_CALL(*sink, Start());
+    EXPECT_CALL(*sink, Stop());
+    return sink;
+  }
+};
+
+class AudioRendererMixerManagerTest : public testing::Test {
+ public:
+  AudioRendererMixerManagerTest() {
+    // We don't want to deal with instantiating a real AudioDevice since it's
+    // not important to our testing, so use a mock AudioDeviceFactory.
+    mock_sink_factory_.reset(new MockAudioRenderSinkFactory());
+    manager_.reset(new AudioRendererMixerManager());
+  }
+
+  media::AudioRendererMixer* GetMixer(const media::AudioParameters& params) {
+    return manager_->GetMixer(params);
+  }
+
+  void RemoveMixer(const media::AudioParameters& params) {
+    return manager_->RemoveMixer(params);
+  }
+
+  // Number of instantiated mixers.
+  int mixer_count() {
+    return manager_->mixer_map_.size();
+  }
+
+ protected:
+  scoped_ptr<MockAudioRenderSinkFactory> mock_sink_factory_;
+  scoped_ptr<AudioRendererMixerManager> manager_;
+};
+
+// Verify GetMixer() and RemoveMixer() both work as expected; particularly with
+// respect to the explicit ref counting done.
+TEST_F(AudioRendererMixerManagerTest, GetRemoveMixer) {
+  // There should be no mixers outstanding to start with.
+  EXPECT_EQ(mixer_count(), 0);
+
+  media::AudioParameters params1(
+      media::AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate,
+      kBitsPerChannel, kBufferSize);
+
+  media::AudioRendererMixer* mixer1 = GetMixer(params1);
+  ASSERT_TRUE(mixer1);
+  EXPECT_EQ(mixer_count(), 1);
+
+  // The same parameters should return the same mixer1.
+  EXPECT_EQ(mixer1, GetMixer(params1));
+  EXPECT_EQ(mixer_count(), 1);
+
+  // Remove the extra mixer we just acquired.
+  RemoveMixer(params1);
+  EXPECT_EQ(mixer_count(), 1);
+
+  media::AudioParameters params2(
+      media::AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate * 2,
+      kBitsPerChannel, kBufferSize * 2);
+  media::AudioRendererMixer* mixer2 = GetMixer(params2);
+  ASSERT_TRUE(mixer2);
+  EXPECT_EQ(mixer_count(), 2);
+
+  // Different parameters should result in a different mixer1.
+  EXPECT_NE(mixer1, mixer2);
+
+  // Remove both outstanding mixers.
+  RemoveMixer(params1);
+  EXPECT_EQ(mixer_count(), 1);
+  RemoveMixer(params2);
+  EXPECT_EQ(mixer_count(), 0);
+
+  // Verify the old mixer was actually removed and we get a new one if we send
+  // the same audio parameters again.
+  EXPECT_NE(mixer1, GetMixer(params1));
+  EXPECT_EQ(mixer_count(), 1);
+  RemoveMixer(params1);
+}
+
+// Verify CreateInput() provides AudioRendererMixerInput with the appropriate
+// callbacks and they are working as expected.
+TEST_F(AudioRendererMixerManagerTest, CreateInput) {
+  media::AudioParameters params(
+      media::AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate,
+      kBitsPerChannel, kBufferSize);
+
+  // Create an a mixer input and ensure it doesn't instantiate a mixer yet.
+  EXPECT_EQ(mixer_count(), 0);
+  scoped_refptr<media::AudioRendererMixerInput> input(manager_->CreateInput());
+  EXPECT_EQ(mixer_count(), 0);
+
+  // Implicitly test that AudioRendererMixerInput was provided with the expected
+  // callbacks needed to acquire an AudioRendererMixer and remove it.
+  media::FakeAudioRenderCallback callback(0);
+  input->Initialize(params, &callback);
+  EXPECT_EQ(mixer_count(), 1);
+
+  // Destroying the input should destroy the mixer.
+  input = NULL;
+  EXPECT_EQ(mixer_count(), 0);
+}