Disk cache: Add the name of the relevant flag to

      truncated entries on the view-cache details page.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/502021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@34643 0039d316-1c4b-4281-b951-d872f2087c98