Referrer Policy: Add new policies to URLRequest.

net/url_request/url_request.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_URL_REQUEST_URL_REQUEST_H_
 #define NET_URL_REQUEST_URL_REQUEST_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 76 matching lines @@
   enum {
 #define HTTP_ATOM(x) HTTP_ ## x,
 #include "net/http/http_atom_list.h"
 #undef HTTP_ATOM
   };
 
   // Referrer policies (see set_referrer_policy): During server redirects, the
   // referrer header might be cleared, if the protocol changes from HTTPS to
   // HTTP. This is the default behavior of URLRequest, corresponding to
   // CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE. Alternatively, the
-  // referrer policy can be set to never change the referrer header. This
-  // behavior corresponds to NEVER_CLEAR_REFERRER. Embedders will want to use
-  // NEVER_CLEAR_REFERRER when implementing the meta-referrer support
-  // (http://wiki.whatwg.org/wiki/Meta_referrer) and sending requests with a
-  // non-default referrer policy. Only the default referrer policy requires
-  // the referrer to be cleared on transitions from HTTPS to HTTP.
+  // referrer policy can be set to strip the referrer down to an origin upon
+  // cross-origin navigation (ORIGIN_ONLY_ON_TRANSITION_CROSS_ORIGIN), or
+  // never change the referrer header (NEVER_CLEAR_REFERRER). Embedders will
+  // want to use these options when implementing referrer policy support
+  // (https://w3c.github.io/webappsec/specs/referrer-policy/).
+  //
+  // REDUCE_REFERRER_GRANULARITY_ON_TRANSITION_CROSS_ORIGIN is a slight variant
+  // on CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE: if the request is
+  // redirected cross-origin, but does not degrade to an insecure connection,
+  // the referrer will be delivered with reduced granularity (e.g. an origin
+  // rather than a full URL).

[mmenke, 2014/11/19 16:29:03]

I don't think your last paragraph makes it sufficiently clear that it's applied
to HTTP->HTTP and HTTP->HTTPS redirects, in addition to HTTPS->HTTPS ones.

[Mike West, 2014/11/20 10:45:30]

Attempted to clarify. WDYT?

   enum ReferrerPolicy {
     CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE,
+    REDUCE_REFERRER_GRANULARITY_ON_TRANSITION_CROSS_ORIGIN,
+    ORIGIN_ONLY_ON_TRANSITION_CROSS_ORIGIN,
     NEVER_CLEAR_REFERRER,
   };
 
   // First-party URL redirect policy: During server redirects, the first-party
   // URL for cookies normally doesn't change. However, if the request is a
   // top-level first-party request, the first-party URL should be updated to the
   // URL on every redirect.
   enum FirstPartyURLPolicy {
     NEVER_CHANGE_FIRST_PARTY_URL,
     UPDATE_FIRST_PARTY_URL_ON_REDIRECT,
@@ skipping 172 matching lines @@
   static std::string ComputeMethodForRedirect(const std::string& method,
                                               int http_status_code);
 
   // The referrer URL for the request.  This header may actually be suppressed
   // from the underlying network request for security reasons (e.g., a HTTPS
   // URL will not be sent as the referrer for a HTTP request).  The referrer
   // may only be changed before Start() is called.
   const std::string& referrer() const { return referrer_; }
   // Referrer is sanitized to remove URL fragment, user name and password.
   void SetReferrer(const std::string& referrer);
+  // Returns true if the referrer is invalid for this request, given its
+  // referrer policy. This could mean that a secure referrer is set for a
+  // request which should have dropped it, or that a full referrer url is set
+  // for a request which should have trimmed it to an origin.
+  bool IsReferrerInvalid() const;
 
   // The referrer policy to apply when updating the referrer during redirects.
   // The referrer policy may only be changed before Start() is called.
   ReferrerPolicy referrer_policy() const { return referrer_policy_; }
   void set_referrer_policy(ReferrerPolicy referrer_policy);
 
   // Sets the delegate of the request.  This value may be changed at any time,
   // and it is permissible for it to be null.
   void set_delegate(Delegate* delegate);
 
@@ skipping 527 matching lines @@
 
   // The proxy server used for this request, if any.
   HostPortPair proxy_server_;
 
   DISALLOW_COPY_AND_ASSIGN(URLRequest);
 };
 
 }  // namespace net
 
 #endif  // NET_URL_REQUEST_URL_REQUEST_H_