Fix GPU displacement with expanding crop rects.

Fix GPU displacement with expanding crop rects, and re-enable the
imagefilterscropexpand GM. There were two bugs: the result texture was
being created at input color bitmap size, not the cropped bounds size,
and the matrix in GrContext was not being set to identity before draw.

R=junov@chromium.org

Review URL: https://codereview.chromium.org/195973007

git-svn-id: http://skia.googlecode.com/svn/trunk@13844 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed