Implement new referrer policies

ios/web/public/referrer_util.cc

Index: ios/web/public/referrer_util.cc
diff --git a/ios/web/public/referrer_util.cc b/ios/web/public/referrer_util.cc
index 4bee17fd304f579acb50cb775e131d6d14751b7b..f5722933aff4726dbd53525243e991c5a13837cb 100644
--- a/ios/web/public/referrer_util.cc
+++ b/ios/web/public/referrer_util.cc
@@ -31,6 +31,20 @@ std::string ReferrerHeaderValueForNavigation(
       if (referrer.url.GetOrigin() != destination.GetOrigin())
         return referrer.url.GetOrigin().spec();
       return referrer.url.GetAsReferrer().spec();
+    case ReferrerPolicySameOrigin:
+      if (referrer.url.GetOrigin() != destination.GetOrigin())
+        return std::string();
+      return referrer.url.GetAsReferrer().spec();
+    case ReferrerPolicyStrictOrigin:
+      if (is_downgrade)
+        return std::string();
+      return referrer.url.GetOrigin().spec();
+    case ReferrerPolicyStrictOriginWhenCrossOrigin:
+      if (is_downgrade)
+        return std::string();
+      if (referrer.url.GetOrigin() != destination.GetOrigin())
+        return referrer.url.GetOrigin().spec();
+      return referrer.url.GetAsReferrer().spec();
   }
   NOTREACHED();
   return std::string();
@@ -43,15 +57,25 @@ net::URLRequest::ReferrerPolicy PolicyForNavigation(
   // resource_dispatcher_host_impl.cc
   switch (referrer.policy) {
     case ReferrerPolicyAlways:
+      return net::URLRequest::NEVER_CLEAR_REFERRER;
     case ReferrerPolicyNever:
+      return net::URLRequest::NO_REFERRER;
     case ReferrerPolicyOrigin:
-      return net::URLRequest::NEVER_CLEAR_REFERRER;
+      return net::URLRequest::ORIGIN;
     case ReferrerPolicyNoReferrerWhenDowngrade:
     case ReferrerPolicyDefault:
       return net::URLRequest::
           CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE;
     case ReferrerPolicyOriginWhenCrossOrigin:
       return net::URLRequest::ORIGIN_ONLY_ON_TRANSITION_CROSS_ORIGIN;
+    case ReferrerPolicySameOrigin:
+      return net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_CROSS_ORIGIN;
+    case ReferrerPolicyStrictOrigin:
+      return net::URLRequest::
+          ORIGIN_CLEAR_ON_TRANSITION_FROM_SECURE_TO_INSECURE;
+    case ReferrerPolicyStrictOriginWhenCrossOrigin:
+      return net::URLRequest::
+          REDUCE_REFERRER_GRANULARITY_ON_TRANSITION_CROSS_ORIGIN;
   }
   NOTREACHED();
   return net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE;
@@ -69,8 +93,13 @@ ReferrerPolicy ReferrerPolicyFromString(const std::string& policy) {
     return ReferrerPolicyOriginWhenCrossOrigin;
   if (policy == "always" || policy == "unsafe-url")
     return ReferrerPolicyAlways;
-  // Note that this is *not* Default; per spec, anything unknown is Never.
-  return web::ReferrerPolicyNever;

[kkhorimoto, 2017/06/08 00:56:46]

It looks like we were intentionally using Never here per the spec above; can you
revert that change?

[estark, 2017/06/08 18:42:57]

Sorry, I should have explained this, but quite a while ago the spec changed to
ignore unknown values:
https://w3c.github.io/webappsec-referrer-policy/#unknown-policy-values

I can do this change in a separate CL if you prefer, but we should make this
change one way or another to match the spec.

+  if (policy == "same-origin")
+    return ReferrerPolicySameOrigin;
+  if (policy == "strict-origin")
+    return ReferrerPolicyStrictOrigin;
+  if (policy == "strict-origin-when-cross-origin")
+    return ReferrerPolicyStrictOriginWhenCrossOrigin;
+  return ReferrerPolicyDefault;
 }
 
 }  // namespace web