We should move the isMainThread predicate function to MainThread.h from Threading.h and consolidate the implementations where possible.
Created attachment 54119 [details] patch
Comment on attachment 54119 [details] patch r=me!
http://trac.webkit.org/changeset/58179 might have broken Qt Linux Release minimal, Qt Linux ARMv5 Release, and Qt Linux ARMv7 Release
Fixed in r58179 and r58181.