webcodecs: Transfer array buffer into VideoFrame ctor

Implementation for w3c/webcodecs#104

Change-Id: Ifbc1fb1739a0bc19dc6db27943fff0cecae0156d

Author: Djuffin

webcodecs/videoFrame-construction.any.js

@@ -755,3 +755,41 @@ test(t => {
   frame.close();
 }, 'Test a VideoFrame constructed from canvas can drop the alpha channel.');
 
+promise_test(async t => {
+  let fmt = 'RGBA';
+  const rgb_plane = [
+    0xBA, 0xDF, 0x00, 0xD0, 0xBA, 0xDF, 0x01, 0xD0, 0xBA, 0xDF, 0x02, 0xD0,
+    0xBA, 0xDF, 0x03, 0xD0
+  ];
+  let data = new Uint8Array(rgb_plane);
+  let unused_buffer = new ArrayBuffer(123);
+  let init = {
+    format: fmt,
+    timestamp: 1234,
+    codedWidth: 2,
+    codedHeight: 2,
+    visibleRect: {x: 0, y: 0, width: 2, height: 2},
+    transfer: [data.buffer, unused_buffer]
+  };
+  assert_equals(data.length, 16, 'data.length');
+  assert_equals(unused_buffer.byteLength, 123, 'unused_buffer.byteLength');
+
+  let frame = new VideoFrame(data, init);
+  assert_equals(frame.format, fmt, 'format');
+  assert_equals(data.length, 0, 'data.length after detach');
+  assert_equals(unused_buffer.byteLength, 0, 'unused_buffer after detach');
+
+  const options = {
+    rect: {x: 0, y: 0, width: init.codedWidth, height: init.codedHeight}
+  };
+  let size = frame.allocationSize(options);
+  let output_data = new Uint8Array(size);
+  let layout = await frame.copyTo(output_data, options);
+  let expected_data = new Uint8Array(rgb_plane);
+  assert_equals(expected_data.length, size, 'expected_data size');
+  for (let i = 0; i < size; i++) {
+    assert_equals(expected_data[i], output_data[i], `expected_data[${i}]`);
+  }
+
+  frame.close();
+}, 'Test transfering ArrayBuffer to VideoFrame');