I have an application that uses multiple WebViews. Nowhere do I set the priority of the render thread through the WebSettings though I still get the exception below.
So
It's cyanogen's fault. https://github.com/CyanogenMod/android_frameworks_base/commit/b963f3c0c64560bcdb1596dd85fe9b0dad6d78c5#L1R712
I have a pile of crash reports on this issue, all from 4.0.4 on many different devices, all of them likely running some form of CM9 (most don't have official ICS releases yet).
I don't have time to yell at them, so hopefully someone else can bring it up in their bug tracker.