MediaCaptureFromElement: add support for audio captureStream().

content/renderer/media/html_audio_element_capturer_source_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 "base/memory/weak_ptr.h"
+#include "base/run_loop.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "content/public/renderer/media_stream_audio_sink.h"
+#include "content/renderer/media/html_audio_element_capturer_source.h"
+#include "content/renderer/media/media_stream_audio_track.h"
+#include "media/audio/null_audio_sink.h"
+#include "media/base/audio_parameters.h"
+#include "media/base/fake_audio_render_callback.h"
+#include "media/blink/webaudiosourceprovider_impl.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/platform/WebString.h"
+#include "third_party/WebKit/public/web/WebHeap.h"
+
+using ::testing::_;
+using ::testing::AllOf;
+using ::testing::InSequence;
+using ::testing::Mock;
+using ::testing::Property;
+
+namespace content {
+
+static const int kNumChannelsForTest = 1;
+static const int kBufferDurationMs = 10;
+
+static const int kAudioTrackSampleRate = 48000;
+static const int kAudioTrackSamplesPerBuffer =
+    kAudioTrackSampleRate * kBufferDurationMs /
+    base::Time::kMillisecondsPerSecond;
+
+ACTION_P(RunClosure, closure) {
+  closure.Run();
+}
+
+//
+class MockMediaStreamAudioSink final : public MediaStreamAudioSink {
+ public:
+  MockMediaStreamAudioSink() : MediaStreamAudioSink() {}
+  ~MockMediaStreamAudioSink() = default;
+
+  MOCK_METHOD1(OnSetFormat, void(const media::AudioParameters& params));
+  MOCK_METHOD2(OnData,
+               void(const media::AudioBus& audio_bus,
+                    base::TimeTicks estimated_capture_time));
+
+  DISALLOW_COPY_AND_ASSIGN(MockMediaStreamAudioSink);
+};
+
+// This test needs to bundle together plenty of objects, namely:
+// - a WebAudioSourceProviderImpl, which in turn needs an Audio Sink, in this
+//  case a NullAudioSink. This is needed to plug HTMLAudioElementCapturerSource
+//  and inject audio.
+// - a WebMediaStreamSource, that owns the HTMLAudioElementCapturerSource under
+//  test, and a WebMediaStreamAudioTrack, that the class under test needs to
+//  connect to in order to operate correctly. This class has an inner content
+//  MediaStreamAudioTrack.
+// - finally, a MockMediaStreamAudioSink to observe captured audio frames, and
+//  that plugs into the former MediaStreamAudioTrack.
+class HTMLAudioElementCapturerSourceTest : public testing::Test {
+ public:
+  HTMLAudioElementCapturerSourceTest()
+      : fake_callback_(0.1),
+        audio_source_(new media::WebAudioSourceProviderImpl(
+            new media::NullAudioSink(base::ThreadTaskRunnerHandle::Get()))) {}
+
+  void SetUp() final {
+    const media::AudioParameters params(
+        media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+        media::GuessChannelLayout(kNumChannelsForTest),
+        kAudioTrackSampleRate /* sample_rate */, 16 /* bits_per_sample */,
+        kAudioTrackSamplesPerBuffer /* frames_per_buffer */);
+    audio_source_->Initialize(params, &fake_callback_);
+
+    blink_audio_source_.initialize(blink::WebString::fromUTF8("audio_id"),
+                                   blink::WebMediaStreamSource::TypeAudio,
+                                   blink::WebString::fromUTF8("audio_track"),
+                                   false /* remote */);
+    blink_audio_track_.initialize(blink_audio_source_.id(),
+                                  blink_audio_source_);
+
+    // |blink_audio_source_| takes ownership of HtmlAudioElementCapturerSource.
+    blink_audio_source_.setExtraData(
+        new HtmlAudioElementCapturerSource(audio_source_.get()));
+    ASSERT_TRUE(source()->ConnectToTrack(blink_audio_track_));
+  }
+
+  void TearDown() override {
+    blink_audio_track_.reset();
+    blink_audio_source_.reset();
+    blink::WebHeap::collectAllGarbageForTesting();
+  }
+
+  HtmlAudioElementCapturerSource* source() const {
+    return static_cast<HtmlAudioElementCapturerSource*>(
+        MediaStreamAudioSource::From(blink_audio_source_));
+  }
+
+  MediaStreamAudioTrack* track() const {
+    return MediaStreamAudioTrack::From(blink_audio_track_);
+  }
+
+  int InjectAudio(media::AudioBus* audio_bus) {
+    return audio_source_->RenderForTesting(audio_bus);
+  }
+
+ protected:
+  const base::MessageLoop message_loop_;
+
+  blink::WebMediaStreamSource blink_audio_source_;
+  blink::WebMediaStreamTrack blink_audio_track_;
+
+  media::FakeAudioRenderCallback fake_callback_;
+  scoped_refptr<media::WebAudioSourceProviderImpl> audio_source_;
+};
+
+// Constructs and destructs all objects. This is a non trivial sequence.
+TEST_F(HTMLAudioElementCapturerSourceTest, ConstructAndDestruct) {
+}
+
+// This test verifies that Audio can be properly captured when injected in the
+// WebAudioSourceProviderImpl.
+TEST_F(HTMLAudioElementCapturerSourceTest, CaptureAudio) {
+  InSequence s;
+
+  base::RunLoop run_loop;
+  base::Closure quit_closure = run_loop.QuitClosure();
+
+  MockMediaStreamAudioSink sink;
+  track()->AddSink(&sink);
+  EXPECT_CALL(sink, OnSetFormat(_)).Times(1);
+  EXPECT_CALL(
+      sink,
+      OnData(AllOf(Property(&media::AudioBus::channels, kNumChannelsForTest),
+                   Property(&media::AudioBus::frames,
+                            kAudioTrackSamplesPerBuffer)),
+             _))
+      .Times(1)
+      .WillOnce(RunClosure(quit_closure));
+
+  std::unique_ptr<media::AudioBus> bus = media::AudioBus::Create(
+      kNumChannelsForTest, kAudioTrackSamplesPerBuffer);
+  InjectAudio(bus.get());
+  run_loop.Run();
+
+  track()->Stop();
+  track()->RemoveSink(&sink);
+}
+
+}  // namespace content