I have clang-format-3.3 installed and it appears to default to stripping one leading slash.

BUG=294188

Review URL: https://chromiumcodereview.appspot.com/24217002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@225705 0039d316-1c4b-4281-b951-d872f2087c98