The Compute Layout and Allocation Size algorithm is rounding up subsampled height but not subsampled width

[youennf]

When reading https://www.w3.org/TR/webcodecs/#videoframe-compute-layout-and-allocation-size, I can see:

• Set computedLayout’s sourceTop to the result of the division of truncated parsedRect.y by sampleHeight, rounded up to the nearest integer.
• Set computedLayout’s sourceHeight to the result of the division of truncated parsedRect.height by sampleHeight, rounded up to the nearest integer.
  On the other hand, the result of the integer division of truncated parsedRect.x by sampleWidth and the result of the integer division of truncated parsedRect.width by sampleWidth are not rounded up.

Looking at Chromium implementation and WPT test webcodecs/videoFrame-odd-size.any.js, it seems rounding up should be applied for width as well.

@sandersdan, thoughts?