Merge AudioRendererImpl and AudioRendererBase; add NullAudioSink

content/browser/renderer_host/media/audio_renderer_host_unittest.cc

Index: content/browser/renderer_host/media/audio_renderer_host_unittest.cc
diff --git a/content/browser/renderer_host/media/audio_renderer_host_unittest.cc b/content/browser/renderer_host/media/audio_renderer_host_unittest.cc
index 6a1287a0b59329725f4cfe92dc34a2dec4125bdf..b4b7188cf36f1b0bf59f0f4a4d357f44ce26ec40 100644
--- a/content/browser/renderer_host/media/audio_renderer_host_unittest.cc
+++ b/content/browser/renderer_host/media/audio_renderer_host_unittest.cc
@@ -43,9 +43,9 @@ static bool IsRunningHeadless() {
 class MockAudioRendererHost : public AudioRendererHost {
  public:
   explicit MockAudioRendererHost(
-      media::AudioManager* audio_manager,
-      content::MediaObserver* media_observer)
-      : AudioRendererHost(audio_manager, media_observer),
+      content::ResourceContext* resource_context,
+      media::AudioManager* audio_manager)
+      : AudioRendererHost(resource_context, audio_manager),
         shared_memory_length_(0) {
   }