[update] update to upstream commit 42a16bc
Squashed 'qtwebkit/' changes from b3b8ed0..0368bb7

0368bb7 [Qt][Mac] Disable QTKit video on OS X.
1810e38 Glyphs may fail to render when using SVG font

git-subtree-dir: qtwebkit
git-subtree-split: 0368bb7e2682d0b187d31bb91618632965351e4d
Merge commit '60fe96696d0dc0709608523869ab871474717ba9'