MediaStream audio: Refactor 3 separate "glue" implementations into one.

content/renderer/media/mock_audio_device_factory.h

+// 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.
+
+#ifndef CONTENT_RENDERER_MEDIA_MOCK_AUDIO_DEVICE_FACTORY_H_
+#define CONTENT_RENDERER_MEDIA_MOCK_AUDIO_DEVICE_FACTORY_H_
+
+#include "content/renderer/media/audio_device_factory.h"
+
+#include "media/base/audio_capturer_source.h"
+#include "media/base/audio_renderer_sink.h"
+#include "testing/gmock/include/gmock/gmock.h"
+
+namespace content {
+
+// MockAudioDeviceFactory creates an instance of this.
+class MockCapturerSource : public media::AudioCapturerSource {
+ public:
+  MockCapturerSource();
+  MOCK_METHOD3(Initialize, void(const media::AudioParameters& params,
+                                CaptureCallback* callback,
+                                int session_id));
+  MOCK_METHOD0(Start, void());
+  MOCK_METHOD0(Stop, void());
+  MOCK_METHOD1(SetAutomaticGainControl, void(bool enable));
+  void SetVolume(double volume) override;
+
+ protected:
+  ~MockCapturerSource() override;
+};
+
+// Creates one MockCapturerSource instance for unit testing. This replaces the
+// need for unit tests to open a real platform audio output. Instantiating this
+// class sets the global content::AudioDeviceFactory implementation to |this|.
+class MockAudioDeviceFactory : public AudioDeviceFactory {
+ public:
+  MockAudioDeviceFactory();
+  ~MockAudioDeviceFactory() override;
+
+  // Returns the MockCapturerSource created by this factory.
+  const scoped_refptr<MockCapturerSource>& mock_capturer_source() const {
+    return mock_capturer_source_;
+  }
+
+  // Returns nullptr.
+  scoped_refptr<media::AudioRendererSink> CreateFinalAudioRendererSink(
+      int render_frame_id,
+      int sesssion_id,
+      const std::string& device_id,
+      const url::Origin& security_origin) override;
+
+  // Returns nullptr.
+  scoped_refptr<media::AudioRendererSink> CreateAudioRendererSink(
+      SourceType source_type,
+      int render_frame_id,
+      int sesssion_id,
+      const std::string& device_id,
+      const url::Origin& security_origin) override;
+
+  // Returns nullptr.
+  scoped_refptr<media::SwitchableAudioRendererSink>
+  CreateSwitchableAudioRendererSink(
+      SourceType source_type,
+      int render_frame_id,
+      int sesssion_id,
+      const std::string& device_id,
+      const url::Origin& security_origin) override;
+
+  // Returns mock_capturer_source_ once. If called a second time, the process
+  // will crash.
+  scoped_refptr<media::AudioCapturerSource> CreateAudioCapturerSource(
+      int render_frame_id) override;
+
+ private:
+  scoped_refptr<MockCapturerSource> mock_capturer_source_;
+  bool did_create_once_;
+
+  DISALLOW_COPY_AND_ASSIGN(MockAudioDeviceFactory);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_AUDIO_DEVICE_FACTORY_H_