[Sync] Ensure referrer is recorded regardless of policy conversion

components/sessions/core/serialized_navigation_entry.cc

 // 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 "components/sessions/core/serialized_navigation_entry.h"
 
 #include <stddef.h>
 
+#include "base/macros.h"
 #include "base/pickle.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/trace_event/memory_usage_estimator.h"
 #include "components/sessions/core/serialized_navigation_driver.h"
 #include "components/sync/base/time.h"
 #include "components/sync/protocol/session_specifics.pb.h"
 
 namespace sessions {
 
 // TODO(treib): Remove, not needed anymore. crbug.com/627747
 const char kSearchTermsKey[] = "search_terms";
 
+// The previous referrer policy value corresponding to |Never|.
+const int kObsoleteReferrerPolicyNever = 2;
+
 SerializedNavigationEntry::SerializedNavigationEntry()
     : index_(-1),
       unique_id_(0),
       transition_type_(ui::PAGE_TRANSITION_TYPED),
       has_post_data_(false),
       post_id_(-1),
       is_overriding_user_agent_(false),
       http_status_code_(0),
       is_restored_(false),
       blocked_state_(STATE_INVALID),
@@ skipping 10 matching lines @@
 SerializedNavigationEntry SerializedNavigationEntry::FromSyncData(
     int index,
     const sync_pb::TabNavigation& sync_data) {
   SerializedNavigationEntry navigation;
   navigation.index_ = index;
   navigation.unique_id_ = sync_data.unique_id();
   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.referrer_url_ = GURL();
+    navigation.referrer_policy_ = kObsoleteReferrerPolicyNever;
   }
   navigation.virtual_url_ = GURL(sync_data.virtual_url());
   navigation.title_ = base::UTF8ToUTF16(sync_data.title());
 
   uint32_t transition = 0;
   if (sync_data.has_page_transition()) {
     switch (sync_data.page_transition()) {
       case sync_pb::SyncEnums_PageTransition_LINK:
         transition = ui::PAGE_TRANSITION_LINK;
         break;
@@ skipping 160 matching lines @@
 
   const std::string encoded_page_state =
       SerializedNavigationDriver::Get()->GetSanitizedPageStateForPickle(this);
   WriteStringToPickle(pickle, &bytes_written, max_size, encoded_page_state);
 
   pickle->WriteInt(transition_type_);
 
   const int type_mask = has_post_data_ ? HAS_POST_DATA : 0;
   pickle->WriteInt(type_mask);
 
-  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);
+  WriteStringToPickle(pickle, &bytes_written, max_size, referrer_url_.spec());
+
+  // This field was deprecated in m61, but we still write it to the pickle for
+  // forwards compatibility.
+  pickle->WriteInt(kObsoleteReferrerPolicyNever);
 
   // Save info required to override the user agent.
   WriteStringToPickle(
       pickle, &bytes_written, max_size,
       original_request_url_.is_valid() ?
       original_request_url_.spec() : std::string());
   pickle->WriteBool(is_overriding_user_agent_);
   pickle->WriteInt64(timestamp_.ToInternalValue());
 
   WriteString16ToPickle(pickle, &bytes_written, max_size, search_terms_);
@@ skipping 29 matching lines @@
 
   if (has_type_mask) {
     has_post_data_ = type_mask & HAS_POST_DATA;
     // the "referrer" property was added after type_mask to the written
     // stream. As such, we don't fail if it can't be read.
     std::string referrer_spec;
     if (!iterator->ReadString(&referrer_spec))
       referrer_spec = std::string();
     referrer_url_ = GURL(referrer_spec);
 
-    // The "referrer policy" property was added even later, so we fall back to
-    // the default policy if the property is not present.
-    //
-    // 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();
-    }
+    // Note: due to crbug.com/450589 the initial referrer policy is incorrect,
+    // and ignored. A correct referrer policy is extracted later (see
+    // |correct_referrer_policy| below).
+    int ignored_referrer_policy;
+    ignore_result(iterator->ReadInt(&ignored_referrer_policy));
 
     // If the original URL can't be found, leave it empty.
     std::string original_request_url_spec;
     if (!iterator->ReadString(&original_request_url_spec))
       original_request_url_spec = std::string();
     original_request_url_ = GURL(original_request_url_spec);
 
     // Default to not overriding the user agent if we don't have info.
     if (!iterator->ReadBool(&is_overriding_user_agent_))
       is_overriding_user_agent_ = false;
@@ skipping 10 matching lines @@
       search_terms_.clear();
 
     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;
       encoded_page_state_ =
           SerializedNavigationDriver::Get()->StripReferrerFromPageState(
               encoded_page_state_);
     }
 
     int extended_info_map_size = 0;
     if (iterator->ReadInt(&extended_info_map_size) &&
         extended_info_map_size > 0) {
       for (int i = 0; i < extended_info_map_size; ++i) {
         std::string key;
         std::string value;
         if (iterator->ReadString(&key) && iterator->ReadString(&value))
           extended_info_map_[key] = value;
       }
     }
   }
 
   SerializedNavigationDriver::Get()->Sanitize(this);
 
   is_restored_ = true;
 
   return true;
 }
 
 // TODO(zea): perhaps sync state (scroll position, form entries, etc.) as well?
 // See http://crbug.com/67068.
 sync_pb::TabNavigation SerializedNavigationEntry::ToSyncData() const {
   sync_pb::TabNavigation sync_data;
   sync_data.set_virtual_url(virtual_url_.spec());
-  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_referrer(referrer_url_.spec());
   sync_data.set_correct_referrer_policy(referrer_policy_);
   sync_data.set_title(base::UTF16ToUTF8(title_));
 
   // Page transition core.
   static_assert(static_cast<int32_t>(ui::PAGE_TRANSITION_LAST_CORE) ==
                 static_cast<int32_t>(ui::PAGE_TRANSITION_KEYWORD_GENERATED),
                 "PAGE_TRANSITION_LAST_CORE must equal "
                 "PAGE_TRANSITION_KEYWORD_GENERATED");
   switch (ui::PageTransitionStripQualifier(transition_type_)) {
     case ui::PAGE_TRANSITION_LINK:
@@ skipping 121 matching lines @@
       EstimateMemoryUsage(encoded_page_state_) +
       EstimateMemoryUsage(original_request_url_) +
       EstimateMemoryUsage(search_terms_) +
       EstimateMemoryUsage(favicon_url_) +
       EstimateMemoryUsage(redirect_chain_) +
       EstimateMemoryUsage(content_pack_categories_) +
       EstimateMemoryUsage(extended_info_map_);
 }
 
 }  // namespace sessions