Integrate new extension cache for non-user specific extensions/apps

This CL deprecates all caching mechanism and switching to new mechanism
that works for all default apps and preserve unused cache items for 30 days
or until cache limit reached.

BUG=316371
TEST=existing tests + manual testing
R=joaodasilva@chromium.org, miket@chromium.org, yoz@chromium.org

Review URL: https://codereview.chromium.org/135643007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246995 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246995