Adding support for NOTREECHECKS.

The motivation for this CL is https://codereview.appspot.com/22410044/ ('One-Click Revert in Rietveld'). One of the main use-cases of One-Click revert is to be able to do a quick revert of a breaking change when the tree is closed.

Review URL: https://codereview.chromium.org/68113009

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/commit-queue@235127 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed