ANGLE: Invalidate client window area when resetting swap chain

ANGLE: Invalidate client window area when resetting swap chain

Resizing a window larger results in the newly exposed region being
invalidated but the old region is treated as valid. This can result in
the old region no longer updating. This has been observed on Windows 7
64-bit with Aero theme using NVIDIA GeForce GTS 250 and driver version
301.42. Invalidate the entire client window area when resetting the
swap chain so that it updates properly.

Upstream patch: https://codereview.appspot.com/6812076/

Task-number: QTBUG-27822
Change-Id: I0f5d2004576019458baee74c35e52f69b893a219
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>