Move referrer policy to a different field when serializing.

components/sessions/serialized_navigation_entry.cc

Index: components/sessions/serialized_navigation_entry.cc
diff --git a/components/sessions/serialized_navigation_entry.cc b/components/sessions/serialized_navigation_entry.cc
index 4b041427bdca4ac042b1326acfb4094fe4e8f059..ab950595ec339e1fe4db5a5a019197bd02e68fa7 100644
--- a/components/sessions/serialized_navigation_entry.cc
+++ b/components/sessions/serialized_navigation_entry.cc
@@ -36,8 +36,19 @@ SerializedNavigationEntry SerializedNavigationEntry::FromSyncData(
   SerializedNavigationEntry navigation;
   navigation.index_ = index;
   navigation.unique_id_ = sync_data.unique_id();
-  navigation.referrer_url_ = GURL(sync_data.referrer());
-  navigation.referrer_policy_ = sync_data.referrer_policy();
+  if (sync_data.has_correct_referrer_policy()) {
+    navigation.referrer_url_ = GURL(sync_data.referrer());
+    navigation.referrer_policy_ = sync_data.correct_referrer_policy();
+  } else {
+    int mapped_referrer_policy;
+    if (SerializedNavigationDriver::Get()->MapReferrerPolicyToNewValues(
+            sync_data.obsolete_referrer_policy(), &mapped_referrer_policy)) {
+      navigation.referrer_url_ = GURL(sync_data.referrer());
+    } else {
+      navigation.referrer_url_ = GURL();
+    }
+    navigation.referrer_policy_ = mapped_referrer_policy;
+  }
   navigation.virtual_url_ = GURL(sync_data.virtual_url());
   navigation.title_ = base::UTF8ToUTF16(sync_data.title());
   navigation.encoded_page_state_ = sync_data.state();
@@ -183,12 +194,13 @@ enum TypeMask {
 //
 // type_mask (has_post_data_)
 // referrer_url_
-// referrer_policy_
+// referrer_policy_ (broken, crbug.com/450589)
 // original_request_url_
 // is_overriding_user_agent_
 // timestamp_
 // search_terms_
 // http_status_code_
+// referrer_policy_
 
 void SerializedNavigationEntry::WriteToPickle(int max_size,
                                               Pickle* pickle) const {
@@ -210,11 +222,15 @@ void SerializedNavigationEntry::WriteToPickle(int max_size,
   const int type_mask = has_post_data_ ? HAS_POST_DATA : 0;
   pickle->WriteInt(type_mask);
 
-  WriteStringToPickle(
-      pickle, &bytes_written, max_size,
-      referrer_url_.is_valid() ? referrer_url_.spec() : std::string());
-
-  pickle->WriteInt(referrer_policy_);
+  int mapped_referrer_policy;
+  if (SerializedNavigationDriver::Get()->MapReferrerPolicyToOldValues(
+          referrer_policy_, &mapped_referrer_policy) &&
+      referrer_url_.is_valid()) {
+    WriteStringToPickle(pickle, &bytes_written, max_size, referrer_url_.spec());
+  } else {
+    WriteStringToPickle(pickle, &bytes_written, max_size, std::string());
+  }
+  pickle->WriteInt(mapped_referrer_policy);
 
   // Save info required to override the user agent.
   WriteStringToPickle(
@@ -227,6 +243,8 @@ void SerializedNavigationEntry::WriteToPickle(int max_size,
   WriteString16ToPickle(pickle, &bytes_written, max_size, search_terms_);
 
   pickle->WriteInt(http_status_code_);
+
+  pickle->WriteInt(referrer_policy_);
 }
 
 bool SerializedNavigationEntry::ReadFromPickle(PickleIterator* iterator) {
@@ -258,9 +276,13 @@ bool SerializedNavigationEntry::ReadFromPickle(PickleIterator* iterator) {
 
     // The "referrer policy" property was added even later, so we fall back to
     // the default policy if the property is not present.
-    if (!iterator->ReadInt(&referrer_policy_))
+    //
+    // Note: due to crbug.com/450589 this value might be incorrect, and a
+    // corrected version is stored later in the pickle.
+    if (!iterator->ReadInt(&referrer_policy_)) {
       referrer_policy_ =
           SerializedNavigationDriver::Get()->GetDefaultReferrerPolicy();
+    }
 
     // If the original URL can't be found, leave it empty.
     std::string original_request_url_spec;
@@ -285,6 +307,19 @@ bool SerializedNavigationEntry::ReadFromPickle(PickleIterator* iterator) {
 
     if (!iterator->ReadInt(&http_status_code_))
       http_status_code_ = 0;
+
+    // Correct referrer policy (if present).
+    int correct_referrer_policy;
+    if (iterator->ReadInt(&correct_referrer_policy)) {
+      referrer_policy_ = correct_referrer_policy;
+    } else {
+      int mapped_referrer_policy;
+      if (!SerializedNavigationDriver::Get()->MapReferrerPolicyToNewValues(
+              referrer_policy_, &mapped_referrer_policy)) {
+        referrer_url_ = GURL();
+      }
+      referrer_policy_ = mapped_referrer_policy;
+    }
   }
 
   SerializedNavigationDriver::Get()->Sanitize(this);
@@ -299,8 +334,15 @@ bool SerializedNavigationEntry::ReadFromPickle(PickleIterator* iterator) {
 sync_pb::TabNavigation SerializedNavigationEntry::ToSyncData() const {
   sync_pb::TabNavigation sync_data;
   sync_data.set_virtual_url(virtual_url_.spec());
-  sync_data.set_referrer(referrer_url_.spec());
-  sync_data.set_referrer_policy(referrer_policy_);
+  int mapped_referrer_policy;
+  if (SerializedNavigationDriver::Get()->MapReferrerPolicyToOldValues(
+          referrer_policy_, &mapped_referrer_policy)) {
+    sync_data.set_referrer(referrer_url_.spec());
+  } else {
+    sync_data.set_referrer(std::string());
+  }
+  sync_data.set_obsolete_referrer_policy(mapped_referrer_policy);
+  sync_data.set_correct_referrer_policy(referrer_policy_);
   sync_data.set_title(base::UTF16ToUTF8(title_));
 
   // Page transition core.