MediaRecorder: support sampling rate adaption in AudioTrackRecorder

content/renderer/media/media_recorder_handler_unittest.cc

Index: content/renderer/media/media_recorder_handler_unittest.cc
diff --git a/content/renderer/media/media_recorder_handler_unittest.cc b/content/renderer/media/media_recorder_handler_unittest.cc
index 6989ca68adef2886d764f313243161cfc61a41fc..c31302e2d48ead5e2842efe0743c1be7223467cd 100644
--- a/content/renderer/media/media_recorder_handler_unittest.cc
+++ b/content/renderer/media/media_recorder_handler_unittest.cc
@@ -41,7 +41,8 @@ static const std::string kTestAudioTrackId = "audio_track_id";
 static const int kTestAudioChannels = 2;
 static const int kTestAudioBitsPerSample = 16;
 static const int kTestAudioSampleRate = 48000;
-static const int kTestAudioBufferDurationMS = 60;
+// MediaStream Audio Tack always provides chunks 10 ms of audio data.
+static const int kMediaStreamAudioTrackBufferDurationMs = 10;
 
 struct MediaRecorderTestParams {
   const bool has_video;
@@ -59,7 +60,7 @@ struct MediaRecorderTestParams {
 static const MediaRecorderTestParams kMediaRecorderTestParams[] = {
     {true, false, "video/webm", "vp8", 52, 32, 0, 0},
     {true, false, "video/webm", "vp9", 33, 18, 0, 0},
-    {false, true, "video/webm", "vp8", 0, 0, 990, 706}};
+    {false, true, "video/webm", "vp8", 0, 0, 248, 125}};
 
 class MediaRecorderHandlerTest : public TestWithParam<MediaRecorderTestParams>,
                                  public blink::WebMediaRecorderHandlerClient {
@@ -113,7 +114,7 @@ class MediaRecorderHandlerTest : public TestWithParam<MediaRecorderTestParams>,
   scoped_ptr<media::AudioBus> NextAudioBus() {
     scoped_ptr<media::AudioBus> bus(media::AudioBus::Create(
         kTestAudioChannels,
-        kTestAudioSampleRate * kTestAudioBufferDurationMS / 1000));
+        kTestAudioSampleRate * kMediaStreamAudioTrackBufferDurationMs / 1000));
     audio_source_.OnMoreData(bus.get(), 0, 0);
     return bus;
   }
@@ -286,7 +287,7 @@ TEST_P(MediaRecorderHandlerTest, EncodeAudioFrames) {
   media::AudioParameters params(
       media::AudioParameters::AUDIO_PCM_LINEAR, media::CHANNEL_LAYOUT_STEREO,
       kTestAudioSampleRate, kTestAudioBitsPerSample,
-      kTestAudioSampleRate * kTestAudioBufferDurationMS / 1000);
+      kTestAudioSampleRate * kMediaStreamAudioTrackBufferDurationMs / 1000);
   SetAudioFormatForTesting(params);
 
   {