GitLab

Use ScopedClosureRunner to simplify callback invocation. This ensures
the callback is always either invoked or passed on, and eliminates
the need to DCHECK(!callback.is_null()).

BUG=none
TEST=unit_tests, manual upload tests.


Review URL: https://chromiumcodereview.appspot.com/10825160

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149706 0039d316-1c4b-4281-b951-d872f2087c98