Unittest is being also updated.

TEST=manual
. run ./presubmit_unittest.py, observe success
.create a CL with code style violations (long lines, traling spaces) and observe the violations reported by 'git cl presubmit'

Patch contributed by Vadim

Review URL: http://codereview.chromium.org/6461011

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@74378 0039d316-1c4b-4281-b951-d872f2087c98