Enable StaleWhileRevalidate in experimental features.

To gather some stability enable it for experimental features before
we do the origin trial.

BUG=348877

Change-Id: I7598f35ac87b719305c6efa98c37de2eec8031a4
Reviewed-on: https://chromium-review.googlesource.com/1134883
Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574581}
1 file changed