Updates the parsing of cookie strings to allow a cookie's domain attribute to be set to the empty string. This change will also correct the failing web-platform tests related to an empty string domain. Previously, in Chrome's ParsedCookie class and related unit and web-platform tests, a cookie string with an empty string domain would not set the domain attribute. Functionally, this caused a cookie’s domain value to equal the previously specified domain for this cookie (if present). However, this behavior conflicts with the draft RFC6265bis, as the resulting cookie in this situation should simply be bound to its request url’s host, termed a “host cookie.” Shipping this feature will align Chrome’s behavior with the domain attribute handling described in the draft RFC6265bis, and will improve interoperability with Safari and Firefox by matching their treatment of an empty cookie domain attribute.
This feature is relatively small so we do not expect many risks. To verify this, we landed a UMA metric to measure when a ParsedCookie is set up with more than one domain attribute and one of those domain values is the empty string. Results from stable show that only 0.00005% of cookies currently exhibit this behavior. Additionally, when considering only cookies from unique hosts, the results suggest only 0.00001% of cookies have a host requesting this behavior.
This change will not require debugging support outside of the existing DevTools support for cookies.
Contact emailskyras...@chromium.org, miketa...@chromium.org, jadekessler...@chromium.org