Rename Chromium-Resource-Freshness header

The "Resource-Freshness" header was temporarily named
"Chromium-Resource-Freshness" during development.

Since Chrome policy is to avoid using vendor prefixes, we should not
ship the browser to stable with this header name.

Rename the header to "Resource-Freshness".

TEST=net_unittests
BUG=348877

Review URL: https://codereview.chromium.org/469993008

Cr-Commit-Position: refs/heads/master@{#289978}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289978 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed