Revert of Pass task runners to AudioManager constructor.

media/audio/pulse/audio_manager_pulse.cc

Index: media/audio/pulse/audio_manager_pulse.cc
diff --git a/media/audio/pulse/audio_manager_pulse.cc b/media/audio/pulse/audio_manager_pulse.cc
index b96728c73c4cbb41f6dbf6ef1052d57405e5a75e..d6e9543183a0f86c8130b1459f8cd6a65e54ef2d 100644
--- a/media/audio/pulse/audio_manager_pulse.cc
+++ b/media/audio/pulse/audio_manager_pulse.cc
@@ -47,13 +47,18 @@
     FILE_PATH_LITERAL("libpulse.so.0");
 #endif
 
-AudioManagerPulse::AudioManagerPulse(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
-    AudioLogFactory* audio_log_factory)
-    : AudioManagerBase(std::move(task_runner),
-                       std::move(worker_task_runner),
-                       audio_log_factory),
+// static
+AudioManager* AudioManagerPulse::Create(AudioLogFactory* audio_log_factory) {
+  scoped_ptr<AudioManagerPulse> ret(new AudioManagerPulse(audio_log_factory));
+  if (ret->Init())
+    return ret.release();
+
+  DVLOG(1) << "PulseAudio is not available on the OS";
+  return NULL;
+}
+
+AudioManagerPulse::AudioManagerPulse(AudioLogFactory* audio_log_factory)
+    : AudioManagerBase(audio_log_factory),
       input_mainloop_(NULL),
       input_context_(NULL),
       devices_(NULL),
@@ -63,18 +68,10 @@
 
 AudioManagerPulse::~AudioManagerPulse() {
   Shutdown();
+
   // The Pulse objects are the last things to be destroyed since Shutdown()
   // needs them.
   DestroyPulse();
-}
-
-bool AudioManagerPulse::Init() {
-  // TODO(alokp): Investigate if InitPulse can happen on the audio thread.
-  // It currently needs to happen on the main thread so that is InitPulse fails,
-  // we can fallback to ALSA implementation. Initializing it on audio thread
-  // would unblock the main thread and make InitPulse consistent with
-  // DestroyPulse which happens on the audio thread.
-  return InitPulse();
 }
 
 // Implementation of AudioManager.
@@ -220,7 +217,7 @@
   return native_input_sample_rate_;
 }
 
-bool AudioManagerPulse::InitPulse() {
+bool AudioManagerPulse::Init() {
   DCHECK(!input_mainloop_);
 
 #if defined(DLOPEN_PULSEAUDIO)