This introduces changes from https://chromereviews.googleplex.com/206957013/.

R=akuegel@chromium.org
TBR=pgervais@chromium.org
BUG=471767

Review URL: https://codereview.chromium.org/1156373013

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@295506 0039d316-1c4b-4281-b951-d872f2087c98