Use TracingController for startup tracing

This CL depends on https://codereview.chromium.org/66893003/ (which allows customized trace data file) and https://codereview.chromium.org/66193005/ (which removes TraceLog enable counting).

BUG=none
R=cdn@chromium.org, nduca@chromium.org, piman@chromium.org

Review URL: https://codereview.chromium.org/65343006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236362 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236362