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

content/renderer/media/media_stream_audio_deliverer.h

Index: content/renderer/media/media_stream_audio_deliverer.h
diff --git a/content/renderer/media/media_stream_audio_deliverer.h b/content/renderer/media/media_stream_audio_deliverer.h
deleted file mode 100644
index 80a6a1c419382d8115d40e85d7ef8b9d7af8fc92..0000000000000000000000000000000000000000
--- a/content/renderer/media/media_stream_audio_deliverer.h
+++ /dev/null
@@ -1,156 +0,0 @@
-// 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_MEDIA_STREAM_AUDIO_DELIVERER_H_
-#define CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_DELIVERER_H_
-
-#include <algorithm>
-#include <vector>
-
-#include "base/synchronization/lock.h"
-#include "base/threading/thread_checker.h"
-#include "media/base/audio_parameters.h"
-
-namespace content {
-
-// Template containing functionality common to both MediaStreamAudioSource and
-// MediaStreamAudioTrack. This is used for managing the connections between
-// objects through which audio data flows, and doing so in a thread-safe manner.
-//
-// The Consumer parameter of the template is the type of the objects to which
-// audio data is delivered: MediaStreamAudioTrack or MediaStreamAudioSink. It's
-// assumed the Consumer class defines methods named OnSetFormat() and OnData()
-// that have the same signature as the ones defined in this template.
-// MediaStreamAudioDeliverer will always guarantee the Consumer's OnSetFormat()
-// and OnData() methods are called sequentially.
-template <typename Consumer>
-class MediaStreamAudioDeliverer {
- public:
-  MediaStreamAudioDeliverer() {}
-  ~MediaStreamAudioDeliverer() {}
-
-  // Returns the current audio parameters. These will be invalid before the
-  // first call to OnSetFormat(). This method is thread-safe.
-  media::AudioParameters GetAudioParameters() const {
-    base::AutoLock auto_lock(params_lock_);
-    return params_;
-  }
-
-  // Begin delivering audio to |consumer|. The caller must guarantee |consumer|
-  // is not destroyed until after calling RemoveConsumer(consumer). This method
-  // must be called on the main thread.
-  void AddConsumer(Consumer* consumer) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    DCHECK(consumer);
-    base::AutoLock auto_lock(consumers_lock_);
-    DCHECK(std::find(consumers_.begin(), consumers_.end(), consumer) ==
-           consumers_.end());
-    DCHECK(std::find(pending_consumers_.begin(), pending_consumers_.end(),
-                     consumer) == pending_consumers_.end());
-    pending_consumers_.push_back(consumer);
-  }
-
-  // Stop delivering audio to |consumer|. Returns true if |consumer| was the
-  // last consumer removed, false otherwise. When this method returns, no
-  // further calls will be made to OnSetFormat() or OnData() on any thread.
-  // This method must be called on the main thread.
-  bool RemoveConsumer(Consumer* consumer) {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    base::AutoLock auto_lock(consumers_lock_);
-    const bool had_consumers =
-        !consumers_.empty() || !pending_consumers_.empty();
-    auto it = std::find(consumers_.begin(), consumers_.end(), consumer);
-    if (it != consumers_.end()) {
-      consumers_.erase(it);
-    } else {
-      it = std::find(pending_consumers_.begin(), pending_consumers_.end(),
-                     consumer);
-      if (it != pending_consumers_.end())
-        pending_consumers_.erase(it);
-    }
-    return had_consumers && consumers_.empty() && pending_consumers_.empty();
-  }
-
-  // Returns the current list of connected Consumers. This is normally used to
-  // send a notification to all consumers. This method must be called on the
-  // main thread.
-  void GetConsumerList(std::vector<Consumer*>* consumer_list) const {
-    DCHECK(thread_checker_.CalledOnValidThread());
-    base::AutoLock auto_lock(consumers_lock_);
-    *consumer_list = consumers_;
-    consumer_list->insert(consumer_list->end(),
-                          pending_consumers_.begin(), pending_consumers_.end());
-  }
-
-  // Change the format of the audio passed in the next call to OnData(). This
-  // method may be called on any thread but, logically, should only be called
-  // between calls to OnData().
-  void OnSetFormat(const media::AudioParameters& params) {
-    DCHECK(params.IsValid());
-    base::AutoLock auto_lock(consumers_lock_);
-    {
-      base::AutoLock auto_params_lock(params_lock_);
-      if (params_.Equals(params))
-        return;
-      params_ = params;
-    }
-    pending_consumers_.insert(pending_consumers_.end(),
-                              consumers_.begin(), consumers_.end());
-    consumers_.clear();
-  }
-
-  // Deliver data to all consumers. This method may be called on any thread.
-  void OnData(const media::AudioBus& audio_bus,
-              base::TimeTicks reference_time) {
-    base::AutoLock auto_lock(consumers_lock_);
-
-    // Call OnSetFormat() for all pending consumers and move them to the
-    // active-delivery list.
-    if (!pending_consumers_.empty()) {
-      const media::AudioParameters params = GetAudioParameters();
-      DCHECK(params.IsValid());
-      for (Consumer* consumer : pending_consumers_)
-        consumer->OnSetFormat(params);
-      consumers_.insert(consumers_.end(),
-                        pending_consumers_.begin(), pending_consumers_.end());
-      pending_consumers_.clear();
-    }
-
-    // Deliver the audio data to each consumer.
-    for (Consumer* consumer : consumers_)
-      consumer->OnData(audio_bus, reference_time);
-  }
-
- private:
-  // In debug builds, check that all methods that could cause object graph or
-  // data flow changes are being called on the main thread.
-  base::ThreadChecker thread_checker_;
-
-  // Protects concurrent access to |pending_consumers_| and |consumers_|.
-  mutable base::Lock consumers_lock_;
-
-  // Any consumers needing a call to OnSetFormat(), to be notified of the
-  // changed audio format, are placed in this list. This includes consumers
-  // added via AddConsumer() that need to have an initial OnSetFormat() call
-  // before audio data is first delivered. Consumers are moved from this list to
-  // |consumers_| on the audio thread.
-  std::vector<Consumer*> pending_consumers_;
-
-  // Consumers that are up-to-date on the current audio format and are receiving
-  // audio data are placed in this list.
-  std::vector<Consumer*> consumers_;
-
-  // Protects concurrent access to |params_|.
-  mutable base::Lock params_lock_;
-
-  // Specifies the current format of the audio passing through this
-  // MediaStreamAudioDeliverer.
-  media::AudioParameters params_;
-
-  DISALLOW_COPY_AND_ASSIGN(MediaStreamAudioDeliverer);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_MEDIA_MEDIA_STREAM_AUDIO_DELIVERER_H_