Make GMs aware of what tool they're being run in.

Add a saveLayer set of draws to convex_poly_clip and fix GPU bug where polygon clips don't account for the translation between clip and device space.

BUG=skia:2051
R=robertphillips@google.com, reed@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/148283017

git-svn-id: http://skia.googlecode.com/svn/trunk@13371 2bbb7eff-a529-9590-31e7-b0007b416f81
8 files changed