Fix close algorithm for non-null VideoFrame timestamps.

Timestamp shouldn't be null anymore, so remove language around setting it to null.

Author: dalecurtis

index.src.html

@@ -2037,7 +2037,7 @@
 run these steps:
 1. If {{AudioEncoderConfig/codec}} is not a <a>valid codec string</a>, return
     `false`.
-2. If the {{AudioEncoderConfig}} has a codec-specific extension and the corresponding 
+2. If the {{AudioEncoderConfig}} has a codec-specific extension and the corresponding
     registration in the [[WEBCODECS-CODEC-REGISTRY]] defines steps to check whether
     the extension is a valid extension, return the result of running those steps.
 3. Return `true`.
@@ -3863,9 +3863,7 @@
         {{VideoFrame/[[visible top]]}}, {{VideoFrame/[[visible width]]}},
         {{VideoFrame/[[visible height]]}}, {{VideoFrame/[[display width]]}},
         and {{VideoFrame/[[display height]]}}.
-    5. Assign `null` to |frame|'s {{VideoFrame/[[duration]]}} and
-        {{VideoFrame/[[timestamp]]}}.
-    6. Assign a new {{VideoFrameMetadata}} to |frame|.{{VideoFrame/[[metadata]]}}.
+    5. Assign a new {{VideoFrameMetadata}} to |frame|.{{VideoFrame/[[metadata]]}}.
 
 : <dfn for=VideoFrame>Parse VideoFrameCopyToOptions</dfn> (with |options|)
 ::  1. Let |defaultRect| be the result of performing the getter steps for