Bug 1694842 [wpt PR 27772] - [webcodecs] Implement transfer semantics for VideoFrame, a=testonly

Automatic update from web-platform-tests
[webcodecs] Implement transfer semantics for VideoFrame

This CL adds paths for modules to implement transfer semantics:

  - ExtractTransferables() is split into the outer loop (stays in
    SerializedScriptValue) and the inner per-object processing which
    moves into V8ScriptValueSerializer. Modules can add implementations
    to V8ScriptValueSerializerForModules.

  - Transferables gains a generic TransferList map modelled after
    SerializedScriptValue::Attachment. The TransferList API includes a
    method for finalizing transfers, which is called from
    V8ScriptValueSerializer::FinalizeTransfer().

Using these APIs, transfer of VideoFrames is then implemented
straightforwardly.

Bug: 1178038
Change-Id: Iafdc02b368d09cdb04c6e48ef187a4733b14c0f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2719085
Commit-Queue: Dan Sanders <sandersd@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Cr-Commit-Position: refs/heads/master@{#873099}

--

wpt-commits: 9dfd4b723781cf12e10810e2b758d56792b008ab
wpt-pr: 27772

testing/web-platform/tests/webcodecs/video-frame-serialization.any.js

@@ -72,9 +72,25 @@ async_test(t => {
   })
 
   localPort.postMessage(localFrame);
-
 }, 'Verify closing frames does not propagate accross contexts.');
 
+async_test(t => {
+  let localFrame = createDefaultVideoFrame();
+
+  let channel = new MessageChannel();
+  let localPort = channel.port1;
+  let externalPort = channel.port2;
+
+  externalPort.onmessage = t.step_func_done((e) => {
+    let externalFrame = e.data;
+    assert_equals(externalFrame.timestamp, defaultInit.timestamp);
+    externalFrame.close();
+  })
+
+  localPort.postMessage(localFrame, [localFrame]);
+  assert_not_equals(localFrame.timestamp, defaultInit.timestamp);
+}, 'Verify transferring frames closes them.');
+
 async_test(t => {
   let localFrame = createDefaultVideoFrame();