insertable streams: s/chunk/encodedFrame

for consistent terminology

BUG=None

Change-Id: If218439824746294e66f4aeb99009d3ff1683289
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3241144
Reviewed-by: Harald Alvestrand <hta@chromium.org>
Commit-Queue: Philipp Hancke <philipp.hancke@googlemail.com>
Cr-Commit-Position: refs/heads/main@{#934515}

webrtc-encoded-transform/RTCPeerConnection-insertable-streams-simulcast.https.html

@@ -21,11 +21,11 @@
   let receiverSSRCs = []
   pc2.ontrack = t.step_func(e => {
     const receiverTransformer = new TransformStream({
-      async transform(chunk, controller) {
-        let ssrc = chunk.getMetadata().synchronizationSource;
+      async transform(encodedFrame, controller) {
+        let ssrc = encodedFrame.getMetadata().synchronizationSource;
         if (receiverSSRCs.indexOf(ssrc) == -1)
           receiverSSRCs.push(ssrc);
-        controller.enqueue(chunk);
+        controller.enqueue(encodedFrame);
       }
     });
     const receiverStreams = e.receiver.createEncodedStreams();
@@ -54,10 +54,10 @@
   const senderStreams = transceiver.sender.createEncodedStreams();
   let senderSSRCs = [];
   const senderTransformer = new TransformStream({
-    async transform(chunk, controller) {
-      if (senderSSRCs.indexOf(chunk.getMetadata().synchronizationSource) == -1)
-        senderSSRCs.push(chunk.getMetadata().synchronizationSource);
-      controller.enqueue(chunk);
+    async transform(encodedFrame, controller) {
+      if (senderSSRCs.indexOf(encodedFrame.getMetadata().synchronizationSource) == -1)
+        senderSSRCs.push(encodedFrame.getMetadata().synchronizationSource);
+      controller.enqueue(encodedFrame);
     }
   });
   senderStreams.readable