Plumb audio focus support for spitzer clients.

content/renderer/media/audio_renderer_mixer_manager.cc

Index: content/renderer/media/audio_renderer_mixer_manager.cc
diff --git a/content/renderer/media/audio_renderer_mixer_manager.cc b/content/renderer/media/audio_renderer_mixer_manager.cc
index 97d0e153fc7e9e63aafdec3c5e2576de677504d4..fbbfbcaefbe0dc6833caea6d543a7d87e2b855b7 100644
--- a/content/renderer/media/audio_renderer_mixer_manager.cc
+++ b/content/renderer/media/audio_renderer_mixer_manager.cc
@@ -49,8 +49,9 @@ media::AudioRendererMixer* AudioRendererMixerManager::GetMixer(
     const std::string& device_id,
     const url::Origin& security_origin,
     media::OutputDeviceStatus* device_status) {
-  // Effects are not passed through to output creation, so ensure none are set.
-  DCHECK_EQ(params.effects(), media::AudioParameters::NO_EFFECTS);
+  // Only the focusable effect is passed through, so ensure no others are set.
+  DCHECK(params.effects() == media::AudioParameters::NO_EFFECTS ||
+         params.effects() == media::AudioParameters::FOCUSABLE);
 
   const MixerKey key(source_render_frame_id, params, device_id,
                      security_origin);
@@ -108,6 +109,10 @@ media::AudioRendererMixer* AudioRendererMixerManager::GetMixer(
       media::AudioParameters::AUDIO_PCM_LOW_LATENCY, params.channel_layout(),
       sample_rate, 16, buffer_size);
 
+  // Pass through the focusable effect to the output device.
+  if (params.effects() == media::AudioParameters::FOCUSABLE)
+    output_params.set_effects(media::AudioParameters::FOCUSABLE);
+
   // If we've created invalid output parameters, simply pass on the input
   // params and let the browser side handle automatic fallback.
   if (!output_params.IsValid())