Add WebCodecs VideoFrame as CanvasImageSource.

Adding VideoFrame as a CanvasImageSource allows drawImage(),
createImageBitmap(), and texImage() to interoperate with VideoFrames.
VideoFrames are effectively the same as the existing point-in-time
capture done for HTMLVideoElement on each of these interfaces.

This adds a non-normative reference on the WebCodecs spec for the
VideoFrame interface and associated properties to accomplish this.

Bug: w3c/webcodecs#158

Author: dalecurtis

source

@@ -4040,6 +4040,18 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
      <li><dfn data-x-href="https://w3c.github.io/manifest/#dfn-processing-a-manifest">process the manifest</dfn></li>
     </ul>
    </dd>
+
+  <dt>WebCodecs</dt>
+
+   <dd>
+    <p>The following features are defined in <cite>WebCodecs</cite>: <ref spec=WEBCODECS></p>
+
+    <ul class="brief">
+     <li><dfn data-x-href="https://w3c.github.io/webcodecs/#videoframe-interface"><code>VideoFrame</code></dfn> interface.</li>
+     <li><dfn data-x-href="https://w3c.github.io/webcodecs/#dom-videoframe-displaywidth">displayWidth</dfn></li>
+     <li><dfn data-x-href="https://w3c.github.io/webcodecs/#dom-videoframe-displayheight">displayHeight</dfn></li>
+    </ul>
+   </dd>
   </dl>
 
   <hr>
@@ -60202,7 +60214,8 @@ typedef (<span>HTMLOrSVGImageElement</span> or
          <span>HTMLVideoElement</span> or
          <span>HTMLCanvasElement</span> or
          <span>ImageBitmap</span> or
-         <span>OffscreenCanvas</span>) <dfn>CanvasImageSource</dfn>;
+         <span>OffscreenCanvas</span> or
+         <span>VideoFrame</span>) <dfn>CanvasImageSource</dfn>;
 
 enum <dfn>CanvasFillRule</dfn> { "<span data-x="dom-context-2d-fillRule-nonzero">nonzero</span>", "<span data-x="dom-context-2d-fillRule-evenodd">evenodd</span>" };
 
@@ -62684,6 +62697,8 @@ try {
 
    <li><code>ImageBitmap</code></li>
 
+   <li><code>VideoFrame</code></li>
+
   </ul>
 
   <p class="note">Although not formally specified as such, <span>SVG <code>image</code></span>
@@ -62728,6 +62743,7 @@ try {
      <code>DOMException</code>.</p></dd>
 
      <dt><code>ImageBitmap</code></dt>
+     <dt><code>VideoFrame</code></dt>
      <dd><p>If <var>image</var>'s <span>[[Detached]]</span> internal slot value
      is set to true, then throw an <span>"<code>InvalidStateError</code>"</span>
      <code>DOMException</code>.</p></dd>
@@ -62769,6 +62785,10 @@ try {
   <p>When a <code>CanvasImageSource</code> object represents an <code>ImageBitmap</code>, the
   object's bitmap image data must be used as the source image.</p>
 
+  <p>When a <code>CanvasImageSource</code> object represents a <code>VideoFrame</code>, the
+  object's pixel data must be used as the source image, and the source image's dimensions must be the
+  <span>displayWidth</span> and <span>displayHeight</span> of the frame.</p>
+
   <p>An object <var>image</var> <dfn id=the-image-argument-is-not-origin-clean>is not
   origin-clean</dfn> if, switching on <var>image</var>:</p>
 
@@ -95423,6 +95443,23 @@ dictionary <dfn>ImageBitmapOptions</dfn> {
        </li>
       </ol>
      </dd>
+
+     <dt><code>VideoFrame</code>
+     <dd>
+      <ol>
+       <li><p>Set <var>imageBitmap</var>'s <span data-x="concept-ImageBitmap-bitmap-data">bitmap
+       data</span> to a copy of <var>image</var>'s visible pixel data, <span>cropped to the source
+       rectangle with formatting</span>.</p></li>
+
+       <li>
+        <p>Run this step <span>in parallel</span>:</p>
+
+        <ol>
+         <li><p>Resolve <var>p</var> with <var>imageBitmap</var>.</p></li>
+        </ol>
+       </li>
+      </ol>
+     </dd>
     </dl>
    </li>
 
@@ -123482,6 +123519,9 @@ INSERT INTERFACES HERE
    <dt id="refsWEBAUDIO">[WEBAUDIO]</dt>
    <dd>(Non-normative) <cite><a href="https://webaudio.github.io/web-audio-api/">Web Audio API</a></cite>, P. Adenot, H. Choi. W3C.</dd>
 
+   <dt id="refsWEBCODECS">[WEBCODECS]</dt>
+   <dd>(Non-normative) <cite><a href="https://w3c.github.io/webcodecs/">WebCodecs API</a></cite>, C. Cunningham, P. Adenot, B. Aboba. W3C.</dd>
+
    <dt id="refsWEBCRYPTO">[WEBCRYPTO]</dt>
    <dd>(Non-normative) <cite><a href="https://w3c.github.io/webcrypto/Overview.html">Web Cryptography API</a></cite>, M. Watson. W3C.</dd>