Automatically handle converting gl_FragCoord to Skia's y-down device coords.

NOTE: THIS WILL LIKELY REQUIRE GM REBASELINING.

R=robertphillips@google.com,senorblanco@chromium.org
Review URL: https://codereview.appspot.com/6744061

git-svn-id: http://skia.googlecode.com/svn/trunk@6030 2bbb7eff-a529-9590-31e7-b0007b416f81
9 files changed