Second layer of mixing for audio elements.

content/renderer/media/audio_renderer_mixer_manager.h

Index: content/renderer/media/audio_renderer_mixer_manager.h
diff --git a/content/renderer/media/audio_renderer_mixer_manager.h b/content/renderer/media/audio_renderer_mixer_manager.h
index e06ff0c66000ac9b1c9b91472383708dff7c6ef7..9256013cc9364fb6a84a356bfbdd43c3a04aca64 100644
--- a/content/renderer/media/audio_renderer_mixer_manager.h
+++ b/content/renderer/media/audio_renderer_mixer_manager.h
@@ -91,8 +91,6 @@ class CONTENT_EXPORT AudioRendererMixerManager {
     bool operator()(const MixerKey& a, const MixerKey& b) const {
       if (a.source_render_frame_id != b.source_render_frame_id)
         return a.source_render_frame_id < b.source_render_frame_id;
-      if (a.params.sample_rate() != b.params.sample_rate())
-        return a.params.sample_rate() < b.params.sample_rate();
       if (a.params.channels() != b.params.channels())
         return a.params.channels() < b.params.channels();