Add CheckChangeHasOnlyOneEol and CheckChangeHasNoCrAndHasOnlyOneEol.

TEST=unit tests
BUG=none

Review URL: http://codereview.chromium.org/118505

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@18075 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed