Introduce media::AudioPushFifo and a couple of use cases (and clean-ups).

content/renderer/media/webaudio_capturer_source.h

 // 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.
 
 #ifndef CONTENT_RENDERER_MEDIA_WEBAUDIO_CAPTURER_SOURCE_H_
 #define CONTENT_RENDERER_MEDIA_WEBAUDIO_CAPTURER_SOURCE_H_
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "media/audio/audio_parameters.h"
+#include "media/base/audio_bus.h"
 #include "media/base/audio_capturer_source.h"
-#include "media/base/audio_fifo.h"
+#include "media/base/audio_rechunker.h"
 #include "third_party/WebKit/public/platform/WebAudioDestinationConsumer.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
 
 namespace content {
 
 class WebRtcLocalAudioTrack;
 
 // WebAudioCapturerSource is the missing link between
 // WebAudio's MediaStreamAudioDestinationNode and WebRtcLocalAudioTrack.
@@ skipping 24 matching lines @@
   void Start(WebRtcLocalAudioTrack* track);
 
   // Called when the media audio track is stopping.
   void Stop();
 
  protected:
   friend class base::RefCountedThreadSafe<WebAudioCapturerSource>;
   ~WebAudioCapturerSource() override;
 
  private:
+  // Called by AudioRechunker zero or more times during the call to
+  // consumeAudio().  Delivers re-chunked audio data to the track.
+  void DeliverRechunkedAudio(const media::AudioBus& audio_bus,
+                             base::TimeDelta reference_timestamp);
+
   // Removes this object from a blink::WebMediaStreamSource with which it
   // might be registered. The goal is to avoid dangling pointers.
   void removeFromBlinkSource();
 
   // Used to DCHECK that some methods are called on the correct thread.
   base::ThreadChecker thread_checker_;
 
   // The audio track this WebAudioCapturerSource is feeding data to.
   // WebRtcLocalAudioTrack is reference counted, and owning this object.
   // To avoid circular reference, a raw pointer is kept here.
   WebRtcLocalAudioTrack* track_;
 
   media::AudioParameters params_;
 
   // Flag to help notify the |track_| when the audio format has changed.
   bool audio_format_changed_;
 
-  // Wraps data coming from HandleCapture().
+  // A wrapper used for providing audio to |rechunker_|.
   scoped_ptr<media::AudioBus> wrapper_bus_;
 
-  // Bus for reading from FIFO and calling the CaptureCallback.
-  scoped_ptr<media::AudioBus> capture_bus_;
-
-  // Handles mismatch between WebAudio buffer size and WebRTC.
-  scoped_ptr<media::AudioFifo> fifo_;
+  // Takes in the audio data passed to consumeAudio() and re-chunks it into 10
+  // ms chunks for the track.  This ensures each chunk of audio delivered to the
+  // track has the required buffer size, regardless of the amount of audio
+  // provided via each consumeAudio() call.
+  media::AudioRechunker rechunker_;
 
   // Synchronizes HandleCapture() with AudioCapturerSource calls.
   base::Lock lock_;
   bool started_;
 
   // This object registers with a blink::WebMediaStreamSource. We keep track of
   // that in order to be able to deregister before stopping the audio track.
   blink::WebMediaStreamSource blink_source_;
 
   DISALLOW_COPY_AND_ASSIGN(WebAudioCapturerSource);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBAUDIO_CAPTURER_SOURCE_H_