make the filter mode for GrTextureAccess an enum so we can plumb down
the paint's filter modes to the GPU

BUG=
R=bsalomon@google.com

Review URL: https://codereview.chromium.org/20362002

git-svn-id: http://skia.googlecode.com/svn/trunk@10368 2bbb7eff-a529-9590-31e7-b0007b416f81
20 files changed