Looking up device id by session id for AudioRendererMixerInput

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 a245a10294bc02df005fb9408804d4cd82944131..fc182e86a09bcc14b58f8689cbe8181b6f56dccb 100644
--- a/content/renderer/media/audio_renderer_mixer_manager.h
+++ b/content/renderer/media/audio_renderer_mixer_manager.h
@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "content/common/content_export.h"
+#include "media/audio/audio_manager_base.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/output_device_info.h"
 #include "url/origin.h"
@@ -47,10 +48,13 @@ class CONTENT_EXPORT AudioRendererMixerManager {
   // retrieve an AudioRendererMixer instance from AudioRendererMixerManager.
   // |source_render_frame_id| refers to the RenderFrame containing the entity
   // rendering the audio.  Caller must ensure AudioRendererMixerManager outlives
-  // the returned input. |device_id| and |security_origin| identify the output
-  // device to use
+  // the returned input. |device_id|, |session_id| and |security_origin|
+  // identify the output device to use. If |device_id| is empty and |session_id|
+  // is nonzero, output device associated with the opened input device
+  // designated by |session_id| is used. Otherwise, |session_id| is ignored.
   media::AudioRendererMixerInput* CreateInput(
       int source_render_frame_id,
+      int session_id,
       const std::string& device_id,
       const url::Origin& security_origin);
 
@@ -102,6 +106,14 @@ class CONTENT_EXPORT AudioRendererMixerManager {
       if (a.params.channel_layout() != b.params.channel_layout())
         return a.params.channel_layout() < b.params.channel_layout();
 
+      if (media::AudioManagerBase::IsDefaultDeviceId(a.device_id) &&
+          media::AudioManagerBase::IsDefaultDeviceId(b.device_id)) {
+        // Both device IDs represent the same default device => do not compare
+        // them; the default device is always authorized => ignoring security
+        // origin.
+        return false;
+      }
+
       if (a.device_id != b.device_id)
         return a.device_id < b.device_id;