Reduce the clip region in ClipAndDrawGradient
Reduce the clip region in ClipAndDrawGradient

We should reduce OutputDevice's clipping region to the bounds of the
polypolygon. To do this we run OutputDevice::Push(PUSH_CLIPREGION)
to have it set the clip region of the device, then intersect the clip
region of the device with the bounding rectangle.

Change-Id: I58ff5d1def1eca3c1213c7fd2d6a7205b70cdd01

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core