Replace most LOG/CHECK statements with DLOG/DCHECK statements in base.

[ Reland of 107042 http://codereview.chromium.org/8368009 ]

I tried hard not to change CHECKs that had side effects. I kept fatal checks
that seemed security or debugging-info (in crash reports) sensitive, and ones
that seems particularly well-conceived.
Review URL: http://codereview.chromium.org/8341026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107434 0039d316-1c4b-4281-b951-d872f2087c98
56 files changed