Create a private API for controlling WebRTC's AEC3

chrome/common/extensions/api/webrtc_audio_private.idl

Index: chrome/common/extensions/api/webrtc_audio_private.idl
diff --git a/chrome/common/extensions/api/webrtc_audio_private.idl b/chrome/common/extensions/api/webrtc_audio_private.idl
index 32afbd48ee9288b4e4fac6c9807775132584a8e7..dbbf0fd17f19826fc0f71c153573fec697146e81 100644
--- a/chrome/common/extensions/api/webrtc_audio_private.idl
+++ b/chrome/common/extensions/api/webrtc_audio_private.idl
@@ -50,6 +50,11 @@ namespace webrtcAudioPrivate {
     long? guestProcessId;
   };
 
+  dictionary AudioExperiments {
+    // Enables or disables the new acoustic echo canceller (AEC3) in WebRTC.
+    boolean? enableAec3;
+  };
+
   interface Functions {
     // Retrieves a list of available audio sink devices.
     static void getSinks(GetSinksCallback callback);
@@ -75,6 +80,11 @@ namespace webrtcAudioPrivate {
     static void getAssociatedSink(DOMString securityOrigin,
                                   DOMString sourceIdInOrigin,
                                   SinkIdCallback cb);
+
+    // Provides settings to experiments related to WebRTC audio.
+    static void setAudioExperiments(RequestInfo request,

[Devlin, 2017/04/10 21:34:25]

Document the parameters this accepts. Also, probably add an optional callback
unless there's a concrete reason not to.

[Henrik Grunell, 2017/04/11 06:49:39]

I asked the author to remove the callback that was originally there since there
is no need to signal success/failure (and it was actually never run in the
original patch). There's also discussion in another comment whether the
application would need to know when the operation has finished. If that's not
necessary either, I see no reason for a callback.

[hlundin-chromium, 2017/04/11 09:19:37]

Added documentation.

[Devlin, 2017/04/11 20:49:37]

The main reason is consistency with other APIs and because it's difficult to
predict all use cases (it's entirely possible that there could be a reason to
wait for the operation to complete).  But, given it's a private API, we can hold
off if you prefer.

[hlundin-chromium, 2017/04/12 05:54:16]

Time is not on our side now, so I'll prefer to hold off.

+                                    DOMString securityOrigin,
+                                    AudioExperiments audioExperiments);
   };
 
   interface Events {