Revert of Pass task runners to AudioManager constructor.

media/audio/mac/audio_low_latency_input_mac_unittest.cc

Index: media/audio/mac/audio_low_latency_input_mac_unittest.cc
diff --git a/media/audio/mac/audio_low_latency_input_mac_unittest.cc b/media/audio/mac/audio_low_latency_input_mac_unittest.cc
index 7309586422e4024bc18112db95f42a0aa2012b64..ba30cf133e0c755a5282d0a1d61aacc8b7a391c6 100644
--- a/media/audio/mac/audio_low_latency_input_mac_unittest.cc
+++ b/media/audio/mac/audio_low_latency_input_mac_unittest.cc
@@ -107,16 +107,12 @@
  protected:
   MacAudioInputTest()
       : message_loop_(base::MessageLoop::TYPE_UI),
-        audio_manager_(
-            AudioManager::CreateForTesting(message_loop_.task_runner())) {
+        audio_manager_(AudioManager::CreateForTesting()) {
     // Wait for the AudioManager to finish any initialization on the audio loop.
     base::RunLoop().RunUntilIdle();
   }
 
-  ~MacAudioInputTest() override {
-    audio_manager_.reset();
-    base::RunLoop().RunUntilIdle();
-  }
+  ~MacAudioInputTest() override { base::RunLoop().RunUntilIdle(); }
 
   bool InputDevicesAvailable() {
     return audio_manager_->HasAudioInputDevices();
@@ -150,7 +146,7 @@
   }
 
   base::MessageLoop message_loop_;
-  ScopedAudioManagerPtr audio_manager_;
+  scoped_ptr<AudioManager> audio_manager_;
 };
 
 // Test Create(), Close().