Add APIs to expose http cache's metadata and the
the ability to stop caching a given request.

BUG=32406, 22900
TEST=none

Review URL: http://codereview.chromium.org/600167

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@39751 0039d316-1c4b-4281-b951-d872f2087c98
15 files changed