RWHVQDQ::contentsRect can be called by chromium before the view has a window.

Change-Id: I50e3a2ba95b3c0b49af2139f763f11154defe503
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>
Reviewed-by: Michael Bruning <michael.bruning@digia.com>