Test that the 'Expires' header is updated upon successful validation.

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".


--------Testing loads from disk cache--------
response headers: {"Expires":"now(0)","ETag":"match"}
response's 'Expires' header is overriden by future date in 304 response
response source: Disk cache after validation

--------Testing loads through memory cache (XHR behavior)--------
response headers: {"Expires":"now(0)","ETag":"match"}
response's 'Expires' header is overriden by future date in 304 response
response source: Memory cache

--------Testing loads through memory cache (subresource behavior)--------
response headers: {"Expires":"now(0)","ETag":"match"}
response's 'Expires' header is overriden by future date in 304 response
response source: Memory cache

304 response included an 'Expires' header in the future, so we should not need to revalidate this time.
--------Testing loads from disk cache--------
response headers: {"Expires":"now(0)","ETag":"match"}
response's 'Expires' header is overriden by future date in 304 response
response source: Disk cache

--------Testing loads through memory cache (XHR behavior)--------
response headers: {"Expires":"now(0)","ETag":"match"}
response's 'Expires' header is overriden by future date in 304 response
response source: Memory cache

--------Testing loads through memory cache (subresource behavior)--------
response headers: {"Expires":"now(0)","ETag":"match"}
response's 'Expires' header is overriden by future date in 304 response
response source: Memory cache

PASS successfullyParsed is true

TEST COMPLETE