In  Issue 894021  a bug was found in WebGLRenderingContextBase::CopyRenderingResultsFromDrawingBuffer, prompting reexamination of the surrounding code. These code paths are used for printing, WebGL-to-2D drawing, and more.

WebGLRenderingContextBase::GetImage is the fallback path for this method, and it calls back in to CopyRenderingResultsFromDrawingBuffer. This has been the cause of some fuzzing test failures (Issue 890597).

These code paths should be cleaned up.