LayoutTests/fast/canvas/canvas-composite-alpha.html failed at QtLauncher, as well as it works fine on Safari.
Looks like Qt don't fully support composition.
Create a Qt bug to close this one.
Created attachment 61890 [details]
Comment on attachment 61890 [details]
Clearing flags on attachment: 61890
Committed r63654: <http://trac.webkit.org/changeset/63654>
All reviewed patches have been landed. Closing bug.