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

content/renderer/media/webrtc/processed_local_audio_track.cc

 // 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.
 
-#include "base/supports_user_data.h"
+#include "content/renderer/media/webrtc/processed_local_audio_track.h"
 
-namespace base {
+#include "content/renderer/media/webrtc/webrtc_local_audio_track_adapter.h"
 
-SupportsUserData::SupportsUserData() {
-  // Harmless to construct on a different thread to subsequent usage.
-  thread_checker_.DetachFromThread();
+namespace content {
+
+namespace {
+// Used as an identifier for ProcessedLocalAudioTrack::From().
+void* const kClassIdentifier = const_cast<void**>(&kClassIdentifier);
+}  // namespace
+
+ProcessedLocalAudioTrack::ProcessedLocalAudioTrack(
+    scoped_refptr<WebRtcLocalAudioTrackAdapter> adapter)
+    : MediaStreamAudioTrack(true), adapter_(std::move(adapter)) {
+  DCHECK(adapter_);
+  adapter_->SetMediaStreamAudioTrack(MediaStreamAudioTrack::GetWeakPtr());
+
+  DVLOG(1) << "ProcessedLocalAudioTrack::ProcessedLocalAudioTrack()";
 }
 
-SupportsUserData::Data* SupportsUserData::GetUserData(const void* key) const {
+ProcessedLocalAudioTrack::~ProcessedLocalAudioTrack() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  DataMap::const_iterator found = user_data_.find(key);
-  if (found != user_data_.end())
-    return found->second.get();
-  return NULL;
+  DVLOG(1) << "ProcessedLocalAudioTrack::~ProcessedLocalAudioTrack()";
+  // Ensure the track is stopped.
+  MediaStreamAudioTrack::Stop();
 }
 
-void SupportsUserData::SetUserData(const void* key, Data* data) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  user_data_[key] = make_scoped_ptr(data);
+// static
+ProcessedLocalAudioTrack* ProcessedLocalAudioTrack::From(
+    MediaStreamAudioTrack* track) {
+  if (track && track->GetClassIdentifier() == kClassIdentifier)
+    return static_cast<ProcessedLocalAudioTrack*>(track);
+  return nullptr;
 }
 
-void SupportsUserData::RemoveUserData(const void* key) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  user_data_.erase(key);
+void* ProcessedLocalAudioTrack::GetClassIdentifier() const {
+  return kClassIdentifier;
 }
 
-void SupportsUserData::DetachUserDataThread() {
-  thread_checker_.DetachFromThread();
+void ProcessedLocalAudioTrack::SetLevel(
+    scoped_refptr<MediaStreamAudioLevelCalculator::Level> level) {
+  adapter_->SetLevel(std::move(level));
 }
 
-SupportsUserData::~SupportsUserData() {
-  DCHECK(thread_checker_.CalledOnValidThread() || user_data_.empty());
-  DataMap local_user_data;
-  user_data_.swap(local_user_data);
-  // Now this->user_data_ is empty, and any destructors called transitively from
-  // the destruction of |local_user_data| will see it that way instead of
-  // examining a being-destroyed object.
+void ProcessedLocalAudioTrack::SetAudioProcessor(
+    scoped_refptr<MediaStreamAudioProcessor> processor) {
+  adapter_->SetAudioProcessor(std::move(processor));
 }
 
-}  // namespace base
+void ProcessedLocalAudioTrack::SetEnabled(bool enabled) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  MediaStreamAudioTrack::SetEnabled(enabled);
+  if (adapter_.get())
+    adapter_->set_enabled(enabled);
+}
+
+}  // namespace content