Add shutdown type to crash key so that we can reliably tell if a crash happens during shutdown.

BUG=258569
R=rsesek@chromium.org, thestig@chromium.org

Review URL: https://codereview.chromium.org/149393014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248746 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248746