Moved the fake input stream's processing onto the audio worker thread.

content/browser/media/capture/web_contents_audio_muter.cc

Index: content/browser/media/capture/web_contents_audio_muter.cc
diff --git a/content/browser/media/capture/web_contents_audio_muter.cc b/content/browser/media/capture/web_contents_audio_muter.cc
index 4d321927a4f9217be710bd0fd7f177e710864e22..6d25d550d1878cbc4bee48b442cc6a345013e538 100644
--- a/content/browser/media/capture/web_contents_audio_muter.cc
+++ b/content/browser/media/capture/web_contents_audio_muter.cc
@@ -12,7 +12,7 @@
 #include "content/public/browser/web_contents.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager.h"
-#include "media/audio/fake_audio_consumer.h"
+#include "media/audio/fake_audio_worker.h"
 #include "media/base/bind_to_current_loop.h"
 
 namespace content {
@@ -30,14 +30,17 @@ namespace {
 class AudioDiscarder : public media::AudioOutputStream {
  public:
   explicit AudioDiscarder(const media::AudioParameters& params)
-      : consumer_(media::AudioManager::Get()->GetWorkerTaskRunner(), params) {}
+      : worker_(media::AudioManager::Get()->GetWorkerTaskRunner(), params),
+        audio_bus_(media::AudioBus::Create(params)) {}
 
   // AudioOutputStream implementation.
   bool Open() override { return true; }
   void Start(AudioSourceCallback* callback) override {
-    consumer_.Start(base::Bind(&AudioDiscarder::FetchAudioData, callback));
+    worker_.Start(base::Bind(&AudioDiscarder::FetchAudioData,
+                             base::Unretained(this),
+                             callback));
   }
-  void Stop() override { consumer_.Stop(); }
+  void Stop() override { worker_.Stop(); }
   void SetVolume(double volume) override {}
   void GetVolume(double* volume) override { *volume = 0; }
   void Close() override { delete this; }
@@ -45,13 +48,13 @@ class AudioDiscarder : public media::AudioOutputStream {
  private:
   ~AudioDiscarder() override {}
 
-  static void FetchAudioData(AudioSourceCallback* callback,
-                             media::AudioBus* audio_bus) {
-    callback->OnMoreData(audio_bus, 0);
+  void FetchAudioData(AudioSourceCallback* callback) {
+    callback->OnMoreData(audio_bus_.get(), 0);
   }
 
   // Calls FetchAudioData() at regular intervals and discards the data.
-  media::FakeAudioConsumer consumer_;
+  media::FakeAudioWorker worker_;
+  scoped_ptr<media::AudioBus> audio_bus_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioDiscarder);
 };