Move referrer policy to a different field when serializing.

components/sessions/content/content_serialized_navigation_driver.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 "components/sessions/content/content_serialized_navigation_driver.h"
 
 #include "base/memory/singleton.h"
 #include "components/sessions/serialized_navigation_entry.h"
 #include "content/public/common/page_state.h"
 #include "content/public/common/referrer.h"
@@ skipping 15 matching lines @@
 ContentSerializedNavigationDriver::ContentSerializedNavigationDriver() {
 }
 
 ContentSerializedNavigationDriver::~ContentSerializedNavigationDriver() {
 }
 
 int ContentSerializedNavigationDriver::GetDefaultReferrerPolicy() const {
   return blink::WebReferrerPolicyDefault;
 }
 
+bool ContentSerializedNavigationDriver::MapReferrerPolicyToOldValues(
+    int referrer_policy,
+    int* mapped_referrer_policy) const {
+  // "always" and "default" are the same value in all versions.
+  if (referrer_policy == blink::WebReferrerPolicyAlways ||
+      referrer_policy == blink::WebReferrerPolicyDefault) {
+    *mapped_referrer_policy = referrer_policy;
+    return true;
+  }
+
+  // "origin" exists in the old encoding.
+  if (referrer_policy == blink::WebReferrerPolicyOrigin) {
+    *mapped_referrer_policy = 3;
+    return true;
+  }
+
+  // Everything else is mapped to never.
+  *mapped_referrer_policy = 2;
+  return false;
+}
+
+bool ContentSerializedNavigationDriver::MapReferrerPolicyToNewValues(
+    int referrer_policy,
+    int* mapped_referrer_policy) const {
+  // "always" and "default" are the same value in all versions.
+  if (referrer_policy == 0 || referrer_policy == 1) {
+    *mapped_referrer_policy = referrer_policy;
+    return true;
+  }
+
+  // Since we don't know what encoding was used, we map the rest to "never".
+  *mapped_referrer_policy = blink::WebReferrerPolicyNever;
+  return false;
+}
+
 std::string
 ContentSerializedNavigationDriver::GetSanitizedPageStateForPickle(
     const SerializedNavigationEntry* navigation) const {
   if (!navigation->has_post_data_) {
     return navigation->encoded_page_state_;
   }
   content::PageState page_state =
       content::PageState::CreateFromEncodedData(
           navigation->encoded_page_state_);
   return page_state.RemovePasswordData().ToEncodedData();
@@ skipping 16 matching lines @@
     navigation->referrer_policy_ = GetDefaultReferrerPolicy();
     navigation->encoded_page_state_ =
         content::PageState::CreateFromEncodedData(
             navigation->encoded_page_state_)
             .RemoveReferrer()
             .ToEncodedData();
   }
 }
 
 }  // namespace sessions