"When I try and play this video, I see corruption on the edges of the video."
Regressing determined that this was caused by http://trac.webkit.org/changeset/146531.
RenderVideo does not paint a background color if it has a poster attribute, breaking the assumptions of RenderLayer::backgroundIsKnownToBeOpaqueInRect().
But also RenderImage::backgroundIsKnown.... doesn't deal with aspect-ratio resize that RenderVideo does.
Created attachment 199872 [details]
In a future patch, RenderImage should change it's implementation of foregroundIsKnownToBeOpaqueInRect() to take into account object-fit.
Comment on attachment 199872 [details]
Attachment 199872 [details] did not pass mac-wk2-ews (mac-wk2):
New failing tests:
Created attachment 199888 [details]
Archive of layout-test-results from webkit-ews-16 for mac-mountainlion-wk2
The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews.
Bot: webkit-ews-16 Port: mac-mountainlion-wk2 Platform: Mac OS X 10.8.2
The new test is failing with a 0.01% image diff. The artifacts introduced by the .jpg version of the video frame are enough to trigger a image failure.
I've updated the test to clip out the video frame, leaving only the video background visible. This eliminates the 0.01% image diff.
Committed r149232: <http://trac.webkit.org/changeset/149232>