Small optimization for convolution shader: only apply the bounds check in direction of convolution, not both. This requires generating different versions of the shader depending on direction.

R=robertphillips@google.com

Review URL: https://codereview.chromium.org/20789003

git-svn-id: http://skia.googlecode.com/svn/trunk@10417 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed