It appears as though the context lost flag is still true when the context is recreated and the fallback 1x1 black textures are created. As createTexture() returns null in the case of a lost context, these textures fail to be created and there's a null pointer deref.
Created attachment 77259 [details]
Comment on attachment 77259 [details]
Committed r74516: <http://trac.webkit.org/changeset/74516>