Pass task runners to AudioManager constructor.

media/audio/sounds/sounds_manager_unittest.cc

Index: media/audio/sounds/sounds_manager_unittest.cc
diff --git a/media/audio/sounds/sounds_manager_unittest.cc b/media/audio/sounds/sounds_manager_unittest.cc
index 6dfcf11939efa994248229f56e5c75048a7d684e..522cf0dc259602e6566591d9eff367cbb333a342 100644
--- a/media/audio/sounds/sounds_manager_unittest.cc
+++ b/media/audio/sounds/sounds_manager_unittest.cc
@@ -26,12 +26,18 @@ class SoundsManagerTest : public testing::Test {
   ~SoundsManagerTest() override {}
 
   void SetUp() override {
-    audio_manager_.reset(AudioManager::CreateForTesting());
+    audio_manager_ =
+        AudioManager::CreateForTesting(message_loop_.task_runner());
     SoundsManager::Create();
   }
 
   void TearDown() override {
     SoundsManager::Shutdown();
+    // AudioStreamHandler destructor posts stop and delete task to audio thread.
+    // Flush audio thread to ensure that those tasks are run before attempting
+    // to destroy AudioManager.
+    base::RunLoop().RunUntilIdle();
+
     audio_manager_.reset();
   }
 
@@ -45,7 +51,7 @@ class SoundsManagerTest : public testing::Test {
   }
 
  private:
-  scoped_ptr<AudioManager> audio_manager_;
+  ScopedAudioManagerPtr audio_manager_;
 
   base::MessageLoop message_loop_;
 };