Add --from-trybot flag in rebaseline.py to enable rebaselining from trybots

(SkipBuildbotRuns)

R=epoger@google.com

Review URL: https://codereview.chromium.org/24153003

git-svn-id: http://skia.googlecode.com/svn/trunk@11294 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed