make generateKeyFrame take a list of rids and return void

making it request a key frame for each rid or all of them if
the list is empty.

Returning a promise resolving with a timestamp is not necessary
since requesting a key frame is something the encoder might
not be able or willing to satisfy.

index.bs

@@ -534,7 +534,7 @@ interface RTCRtpScriptTransformer {
     readonly attribute ReadableStream readable;
     readonly attribute WritableStream writable;
     readonly attribute any options;
-    Promise<unsigned long long> generateKeyFrame(optional DOMString rid);
+    void generateKeyFrame(optional sequence<DOMString> rids);
     Promise<undefined> sendKeyFrameRequest();
 };
 
@@ -575,10 +575,8 @@ Each RTCRtpScriptTransform has the following set of [=association steps=], given
     1. Set |transformer|.`[[encoder]]` to |encoder|.
     1. Set |transformer|.`[[depacketizer]]` to |depacketizer|.
 
-The <dfn method for="RTCRtpScriptTransformer">generateKeyFrame(|rid|)</dfn> method steps are:
-1. Let |promise| be a new promise.
-1. Run the [=generate key frame algorithm=] with |promise|, |this|.`[[encoder]]` and |rid|.
-1. Return |promise|.
+The <dfn method for="RTCRtpScriptTransformer">generateKeyFrame(|rids|)</dfn> method steps are:
+1. Run the [=generate key frame algorithm=] with the {{RTCRtpSender}} associated with |this|.`[[encoder]]` and |rids|.
 
 The <dfn method for="RTCRtpScriptTransformer">sendKeyFrameRequest()</dfn> method steps are:
 1. Let |promise| be a new promise.
@@ -602,37 +600,11 @@ The <dfn attribute for="RTCRtpScriptTransformer">writable</dfn> getter steps are
 
 ## KeyFrame Algorithms ## {#KeyFrame-algorithms}
 
-The <dfn>generate key frame algorithm</dfn>, given |promise|, |encoder| and |rid|, is defined by running these steps:
-1. If |encoder| is undefined, reject |promise| with {{InvalidStateError}}, abort these steps.
-1. If |encoder| is not processing video frames, reject |promise| with {{InvalidStateError}}, abort these steps.
-1. If |rid| is defined, validate its value. If invalid, reject |promise| with {{NotAllowedError}} and abort these steps.
-1. [=In parallel=], run the following steps:
-    1. Gather a list of video encoders, named |videoEncoders| from |encoder|, ordered according negotiated RIDs if any.
-    1. If |rid| is defined, remove from |videoEncoders| any video encoder that does not match |rid|.
-    1. If |rid| is undefined, remove from |videoEncoders| all video encoders except the first one.
-    1. If |videoEncoders| is empty, reject |promise| with {{NotFoundError}} and abort these steps.
-        |videoEncoders| is expected to be empty if the corresponding {{RTCRtpSender}} is not active, or the corresponding {{RTCRtpSender}} track is ended.
-    1. Let |videoEncoder| be the first encoder in |videoEncoders|.
-    1. If |rid| is undefined, set |rid| to the RID value corresponding to |videoEncoder|.
-    1. Create a pending key frame task called |task| with |task|.`[[rid]]` set to rid and |task|.`[[promise]]`| set to |promise|.
-    1. If |encoder|.`[[pendingKeyFrameTasks]]` is undefined, initialize |encoder|.`[[pendingKeyFrameTasks]]` to an empty set.
-    1. Let |shouldTriggerKeyFrame| be <code>true</code> if |encoder|.`[[pendingKeyFrameTasks]]` contains a task whose `[[rid]]`
-        value is equal to |rid|, and <code>false</code> otherwise.
-    1. Add |task| to |encoder|.`[[pendingKeyFrameTasks]]`.
-    1. If |shouldTriggerKeyFrame| is <code>true</code>, instruct |videoEncoder| to generate a key frame for the next provided video frame.
-
-For any {{RTCRtpScriptTransformer}} named |transformer|, the following steps are run just before any |frame| is enqueued in |transformer|.`[[readable]]`:
-1. Let |encoder| be |transformer|.`[[encoder]]`.
-1. If |encoder| or |encoder|.`[[pendingKeyFrameTasks]]` is undefined, abort these steps.
-1. If |frame| is not a video {{RTCEncodedVideoFrameType/"key"}} frame, abort these steps.
-1. For each |task| in |encoder|.`[[pendingKeyFrameTasks]]`, run the following steps:
-    1. If |frame| was generated by a video encoder identified by |task|.`[[rid]]`, run the following steps:
-        1. Remove |task| from |encoder|.`[[pendingKeyFrameTasks]]`.
-        1. Resolve |task|.`[[promise]]` with |frame|'s timestamp.
-
-By resolving the promises just before enqueuing the corresponding key frame in a {{RTCRtpScriptTransformer}}'s readable,
-the resolution callbacks of the promises are always executed just before the corresponding key frame is exposed.
-If the promise is associated to several rid values, it will be resolved when the first key frame corresponding to one the rid value is enqueued.
+The <dfn>generate key frame algorithm</dfn>, given |sender| and |rids|, is defined by running these steps:
+1. If the sender's transceiver kind is not `video`, return an {{OperationError}} and abort these steps.
+1. If |rids| is defined, for each |rid| in rids,
+    1. if |rid| is not associated with |sender|, return an {{InvalidAccessError}} and abort these steps.
+1. Instruct the encoder associated with |sender| to generate a key frame for |rids| or all layers when |rids| is empty.
 
 The <dfn>send request key frame algorithm</dfn>, given |promise| and |depacketizer|, is defined by running these steps:
 1. If |depacketizer| is undefined, reject |promise| with {{InvalidStateError}}, abort these steps.
@@ -649,17 +621,15 @@ An additional API on {{RTCRtpSender}} is added to complement the generation of k
 
 <pre class="idl">
 partial interface RTCRtpSender {
-    Promise&lt;undefined&gt; generateKeyFrame(optional sequence &lt;DOMString&gt; rids);
+    void generateKeyFrame(optional sequence&lt;DOMString&gt; rids);
 };
 </pre>
 
 ## Extension operation ## {#sender-operation}
 
 The <dfn method for="RTCRtpSender">generateKeyFrame(|rids|)</dfn> method steps are:
 
-1. Let |promise| be a new promise.
-1. [=In parallel=], run the [=generate key frame algorithm=] with |promise|, |this|'s encoder and |rids|.
-1. Return |promise|.
+1. Run the [=generate key frame algorithm=] with |this| and |rids|.
 
 # Privacy and security considerations # {#privacy}