Add -r <svn revision> option
Add -r <svn revision> option

TBR=scheib@chromium.org
NOTRY=true



Review URL: https://chromiumcodereview.appspot.com/11959013

git-svn-id: bd64dd6fa6f3f0ed0c0666d1018379882b742947@177228 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

svn2github/chromium-depot-tools,svn2github/chromium-depot-tools,svn2github/chromium-depot-tools