This patch adds the parameter to the filterImageGPU() signature, plumbs through the code on the GPU side, and implements support for it in SkXfermodeImageFilter for both raster and GPU.
Of the remaining filters with GPU implementations, Blur, Morphology, Bicubic and Displacement work fine; they're commutative wrt offset and can simply pass it up the chain. Blend is not, but will be removed shortly anyway (has been replaced with SkXfermodeImageFilter in Blink).
R=reed@google.com, bsalomon@google.com
Author: senorblanco@chromium.org
Review URL: https://chromiumcodereview.appspot.com/15995026
git-svn-id: http://skia.googlecode.com/svn/trunk@9977 2bbb7eff-a529-9590-31e7-b0007b416f81
This fixes the bicubic image filter GM on the GPU, which otherwise draws garbage outside the filtered region. It also moves us closer to unifying the signatures of SkImageFilter::onFilterImage() and SkImageFilter::filterImageGPU().
Review URL: https://codereview.appspot.com/7180048
git-svn-id: http://skia.googlecode.com/svn/trunk@7467 2bbb7eff-a529-9590-31e7-b0007b416f81
