GitLab

Also re-introduces a missing life check in case a request callback deletes the HostResolver.

R=eroman@chromium.org,cbentzel@chromium.org
BUG=115399
TEST=./net_unittest --gtest_filter=HostResolverImplTest.CanceledRequestsReleaseJobSlots


Review URL: http://codereview.chromium.org/9572018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124783 0039d316-1c4b-4281-b951-d872f2087c98