Referrer Policy: Update SanitizeForRequest with new default behavior.

content/public/common/referrer.cc

+// Copyright 2014 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 "base/command_line.h"
+#include "content/public/common/content_switches.h"
+#include "content/public/common/referrer.h"
+
+namespace content {
+
+// static.
+Referrer Referrer::SanitizeForRequest(const GURL& request,
+                                      const Referrer& referrer) {
+  Referrer sanitized_referrer(referrer.url.GetAsReferrer(), referrer.policy);
+
+  if (!request.SchemeIsHTTPOrHTTPS() ||
+      !sanitized_referrer.url.SchemeIsHTTPOrHTTPS()) {
+    sanitized_referrer.url = GURL();
+    return sanitized_referrer;
+  }
+
+  bool is_downgrade =
+      sanitized_referrer.url.SchemeIsSecure() && !request.SchemeIsSecure();
+
+  switch (sanitized_referrer.policy) {
+    case blink::WebReferrerPolicyDefault:
+      if (is_downgrade) {
+        sanitized_referrer.url = GURL();
+      } else if (request.GetOrigin() != sanitized_referrer.url.GetOrigin() &&
+                 base::CommandLine::ForCurrentProcess()->HasSwitch(
+                     switches::kReducedReferrerGranularity)) {
+        sanitized_referrer.url = sanitized_referrer.url.GetOrigin();
+      }
+      break;
+    case blink::WebReferrerPolicyNoReferrerWhenDowngrade:
+      if (is_downgrade)
+        sanitized_referrer.url = GURL();
+      break;
+    case blink::WebReferrerPolicyAlways:
+      break;
+    case blink::WebReferrerPolicyNever:
+      sanitized_referrer.url = GURL();
+      break;
+    case blink::WebReferrerPolicyOrigin:
+      sanitized_referrer.url = sanitized_referrer.url.GetOrigin();
+      break;
+    default:
+      NOTREACHED();
+      break;
+  }
+  return sanitized_referrer;
+}
+
+}  // namespace content