Add support for writing system traces at startup

BUG=275822
TEST=Included in  cl
[email protected], [email protected]

Review URL: https://codereview.chromium.org/23125009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@218498 0039d316-1c4b-4281-b951-d872f2087c98
5 files changed