WCO::ReadyToCommitNavigation was introduced to provide a point in time at which the RenderFrameHost that will navigate is known. Currently it only works with PlzNavigate. A certain number of components would benefit from having it working in the current architecture as well.
In order to do this, we first have to complete the move of the mime sniffing at the beginning of the ResourceHandler chain (see https://codereview.chromium.org/2005273002/#ps160001). Then we plan on merging the CrossSiteResourceHandler with the NavigationResourceThrottle, and take advantage of the IO-UI roundtrip we're making in NavigationResourceThrottle::OnWillProcessResponse to make the decision about whether to transfer the navigation or not there.
Comment 1 by chrishtr@chromium.org
, Jun 21 2016