add some GM tests for rects

BUG=
R=robertphillips@google.com, bsalomon@google.com

Author: yunchao.he@intel.com

Review URL: https://codereview.chromium.org/54213002

git-svn-id: http://skia.googlecode.com/svn/trunk@12073 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed