Because Chrome on iOS relies on the OS cookie line parser (in particular, NSHTTPCookie and its parsing method cookiesWithResponseHeaderFields, see https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSHTTPCookie_Class/#//apple_ref/occ/clm/NSHTTPCookie/cookiesWithResponseHeaderFields:forURL:), we cannot currently control how cookies are parsed.

NSHTTPCookie seems to be pretty much spec compliant, but that leads to some noticeable differences with the de facto standards of all the other UAs, such as with empty-key cookies. See http://inikulin.github.io/cookie-compat/#NAME0028 for an example of where iOS differs, similar to what Safari does.

Chrome is aiming to match these de facto standards, as per  issue 601786 , but we can't do that on iOS. Thus, for now, we are blocking out some tests on iOS, which would fail (such as CookieStoreTest::EmptyKeyTest), but if there comes a day where either NSHTTPCookie matches the de facto standard, or we do our own cookie parsing on iOS, we should re-enable these tests.