Move referrer policy to a different field when serializing.

components/sessions/core/serialized_navigation_driver.h

 // 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.
 
 #ifndef COMPONENTS_SESSIONS_CORE_SERIALIZED_NAVIGATION_DRIVER_H_
 #define COMPONENTS_SESSIONS_CORE_SERIALIZED_NAVIGATION_DRIVER_H_
 
 #include <string>
 
 #include "components/sessions/sessions_export.h"
 
 namespace sessions {
 class SerializedNavigationEntry;
 
 // The SerializedNavigationDriver interface allows SerializedNavigationEntry to
 // obtain information from a singleton driver object. A concrete implementation
 // must be provided by the driver on each platform.
 class SESSIONS_EXPORT_PRIVATE SerializedNavigationDriver {
  public:
   virtual ~SerializedNavigationDriver() {}
 
   // Returns the singleton SerializedNavigationDriver.
   static SerializedNavigationDriver* Get();
 
   // Returns the default referrer policy.
   virtual int GetDefaultReferrerPolicy() const = 0;
 
+  // Maps current referrer policies to old values to work around
+  // crbug.com/450589. Returns false if the referrer should be stripped.
+  virtual bool MapReferrerPolicyToOldValues(
+      int referrer_policy,
+      int* mapped_referrer_policy) const = 0;
+
+  // Sanitizes a referrer policy that might either be in the old or the new
+  // format. Returns false if the referrer should be stripped.
+  virtual bool MapReferrerPolicyToNewValues(
+      int referrer_policy,
+      int* mapped_referrer_policy) const = 0;
+
   // Returns a sanitized version of the given |navigation|'s encoded_page_state
   // suitable for writing to disk.
   virtual std::string GetSanitizedPageStateForPickle(
       const SerializedNavigationEntry* navigation) const = 0;
 
   // Sanitizes the data in the given |navigation| to be more robust against
   // faulty data written by older versions.
   virtual void Sanitize(SerializedNavigationEntry* navigation) const = 0;
 };
 
 }  // namespace sessions
 
 #endif  // COMPONENTS_SESSIONS_CORE_SERIALIZED_NAVIGATION_DRIVER_H_