Upstream (most of) ios/web/public

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
new file mode 100644
index 0000000000000000000000000000000000000000..579ca1b2ace3bd7166f8c0f10d126b5f593b567a
--- /dev/null
+++ b/ios/web/public/referrer_util.cc
@@ -0,0 +1,75 @@
+// Copyright 2013 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.
+
+#include "ios/web/public/referrer_util.h"
+
+#include "base/logging.h"
+#include "ios/web/public/referrer.h"
+#include "url/gurl.h"
+
+namespace web {
+
+GURL ReferrerForHeader(const GURL& referrer) {
+  DCHECK(referrer.is_valid());
+  GURL::Replacements replacements;
+  replacements.ClearUsername();
+  replacements.ClearPassword();
+  replacements.ClearRef();
+  return referrer.ReplaceComponents(replacements);
+}
+
+std::string ReferrerHeaderValueForNavigation(
+    const GURL& destination,
+    const web::Referrer& referrer) {
+  std::string referrer_value;
+  bool leaving_secure_scheme =
+      referrer.url.SchemeIsSecure() && !destination.SchemeIsSecure();
+  if (referrer.policy == ReferrerPolicyAlways ||
+      (referrer.policy == ReferrerPolicyDefault && !leaving_secure_scheme)) {
+    if (referrer.url.is_valid())
+      referrer_value = ReferrerForHeader(referrer.url).spec();
+  } else if (referrer.policy == ReferrerPolicyOrigin) {
+    referrer_value = referrer.url.GetOrigin().spec();
+  } else {
+    // Policy is Never, or it's Default with a secure->insecure transition, so
+    // leave it empty.
+  }
+  return referrer_value;
+}
+
+net::URLRequest::ReferrerPolicy PolicyForNavigation(
+    const GURL& destination,
+    const web::Referrer& referrer) {
+  net::URLRequest::ReferrerPolicy net_referrer_policy =
+      net::URLRequest::CLEAR_REFERRER_ON_TRANSITION_FROM_SECURE_TO_INSECURE;
+  if (referrer.url.is_valid()) {
+    GURL referrer_url(ReferrerHeaderValueForNavigation(destination, referrer));
+    if (!referrer_url.is_empty()) {
+      switch (referrer.policy) {
+        case ReferrerPolicyDefault:
+          break;
+        case ReferrerPolicyAlways:
+        case ReferrerPolicyNever:
+        case ReferrerPolicyOrigin:
+          net_referrer_policy = net::URLRequest::NEVER_CLEAR_REFERRER;
+          break;
+        default:
+          NOTREACHED();
+      }
+    }
+  }
+  return net_referrer_policy;
+}
+
+ReferrerPolicy ReferrerPolicyFromString(const std::string& policy) {
+  if (policy == "never")
+    return ReferrerPolicyNever;
+  if (policy == "always")
+    return ReferrerPolicyAlways;
+  if (policy == "origin")
+    return ReferrerPolicyOrigin;
+  return web::ReferrerPolicyDefault;
+}
+
+}  // namespace web