The first assert in BidiContext only works through sheer luck. The enum WTF::Unicode::Direction has LeftToRight == 0 and RightToLeft == 1 for both ICU and Qt4. Other implementations that have different values for this enum will fail. Fix coming...
Created attachment 44319 [details]
Fix for assert.
style-queue ran check-webkit-style on attachment 44319 [details] without any errors.
Landed with r51697.