[webkit-changes] [WebKit/WebKit] 712b8a: Media recorder produces empty chunks

[youennf]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 712b8a916d0da3c2661c38f3273bc303f3ea431b
      https://github.com/WebKit/WebKit/commit/712b8a916d0da3c2661c38f3273bc303f3ea431b
  Author: Youenn Fablet <youennf at gmail.com>
  Date:   2023-05-24 (Wed, 24 May 2023)

  Changed paths:
    A LayoutTests/http/wpt/mediarecorder/record-context-created-late-expected.txt
    A LayoutTests/http/wpt/mediarecorder/record-context-created-late.html
    M LayoutTests/webrtc/routines.js
    M Source/WebCore/Modules/mediastream/CanvasCaptureMediaStreamTrack.cpp
    M Source/WebCore/html/CanvasBase.cpp
    M Source/WebCore/html/CanvasBase.h

  Log Message:
  -----------
  Media recorder produces empty chunks
https://bugs.webkit.org/show_bug.cgi?id=257016
rdar://109705910

Reviewed by Eric Carlson.

We were skipping video frame generation when needing preparation for display.
This works fine as long as we receive the canvasDisplayBufferPrepared notification.
This notification only happens if the document is observing canvas changes.
If that is not the case, we schedule a capture canvas, which will trigger a video frame generation and will register the document as a canvas change observer.

Making a side fix in LayoutTests/webrtc/routines.js so that computeFrameRate works fine on browsers without internals.
This is necessary for LayoutTests/fast/mediacapturefromelement/CanvasCaptureMediaStream-capture-out-of-DOM-canvas.html in particular.

* LayoutTests/http/wpt/mediarecorder/record-context-created-late-expected.txt: Added.
* LayoutTests/http/wpt/mediarecorder/record-context-created-late.html: Added.
* LayoutTests/webrtc/routines.js:
* Source/WebCore/Modules/mediastream/CanvasCaptureMediaStreamTrack.cpp:
(WebCore::CanvasCaptureMediaStreamTrack::Source::canvasChanged):
* Source/WebCore/html/CanvasBase.cpp:
(WebCore::CanvasBase::hasObserver const):
* Source/WebCore/html/CanvasBase.h:

Canonical link: https://commits.webkit.org/264478@main