UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.23 Safari/537.36

Steps to reproduce the problem:
1. Play a <video>, potentially using MediaSourceExtension (that's the case for us)
2. Upload to texture at 30fps, using:

  gl.bindTexture(gl.TEXTURE_2D, texture)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
  gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1)
  gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, content)
  gl.bindTexture(gl.TEXTURE_2D, null)

// looking at the code now, of course i see potential to use glTexSubImage2D

3. Draw the texture, see that you get approx 5fps of the video frames instead of the 30fps we're looking for

What is the expected behavior?
Smooth display of the video within WebGL

What went wrong?
Chrome 68.x had no problem rendering the video at 60fps. With 69 we see the broken behavior. Please have a look at both screen recordings. 

Did this work before? Yes 68.x

Chrome version: 69.0.3497.23  Channel: beta
OS Version: OS X 10.13.6
Flash Version:
 

Deleted: chrome68.mov 5.0 MB

	chrome68.mov 5.0 MB View Download

Deleted: chrome69.mov 5.7 MB

	chrome69.mov 5.7 MB View Download