add support for high quality image filtering on the GPU

R=bsalomon@google.com, reed@google.com

Review URL: https://codereview.chromium.org/23779003

git-svn-id: http://skia.googlecode.com/svn/trunk/src@11087 2bbb7eff-a529-9590-31e7-b0007b416f81
4 files changed