Adjust preference sync code to only sync user modifiable preferences.

chrome/browser/sync/glue/preference_model_associator.cc

 // Copyright (c) 2010 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 "chrome/browser/sync/glue/preference_model_associator.h"
 
 #include "base/json/json_reader.h"
 #include "base/logging.h"
 #include "base/values.h"
 #include "base/utf_string_conversions.h"
@@ skipping 55 matching lines @@
   base::JSONReader reader;
   for (std::set<std::wstring>::iterator it = synced_preferences_.begin();
        it != synced_preferences_.end(); ++it) {
     std::string tag = WideToUTF8(*it);
     const PrefService::Preference* pref =
         pref_service->FindPreference((*it).c_str());
     DCHECK(pref);
 
     sync_api::WriteNode node(&trans);
     if (node.InitByClientTagLookup(syncable::PREFERENCES, tag)) {
+      // The server has a value for the preference.
       const sync_pb::PreferenceSpecifics& preference(
           node.GetPreferenceSpecifics());
       DCHECK_EQ(tag, preference.name());
 
-      if (!pref->IsManaged()) {
+      if (pref->IsUserModifiable()) {
         scoped_ptr<Value> value(
             reader.JsonToValue(preference.value(), false, false));
         std::wstring pref_name = UTF8ToWide(preference.name());
         if (!value.get()) {
           LOG(ERROR) << "Failed to deserialize preference value: "
                      << reader.GetErrorMessage();
           return false;
         }
 
         // Merge the server value of this preference with the local value.
         scoped_ptr<Value> new_value(MergePreference(*pref, *value));
 
         // Update the local preference based on what we got from the
         // sync server.
         if (!pref->GetValue()->Equals(new_value.get()))
           pref_service->Set(pref_name.c_str(), *new_value);
 
         AfterUpdateOperations(pref_name);
 
         // If the merge resulted in an updated value, write it back to
         // the sync node.
         if (!value->Equals(new_value.get()) &&
             !WritePreferenceToNode(pref->name(), *new_value, &node))
           return false;
       }
       Associate(pref, node.GetId());
-    } else if (!pref->IsManaged()) {
-      // If there is no server value for this preference and it is
-      // currently its default value, don't create a new server node.
-      if (pref->IsDefaultValue())
-        continue;
-
+    } else if (pref->IsUserControlled()) {
+      // The server doesn't have a value, but we have a user-controlled value,
+      // so we push it to the server.
       sync_api::WriteNode write_node(&trans);
       if (!write_node.InitUniqueByCreation(syncable::PREFERENCES, root, tag)) {
         LOG(ERROR) << "Failed to create preference sync node.";
         return false;
       }
 
       // Update the sync node with the local value for this preference.
       if (!WritePreferenceToNode(pref->name(), *pref->GetValue(), &write_node))
         return false;
 
@@ skipping 174 matching lines @@
   // notification to update the UI.
   if (0 == pref_name.compare(prefs::kShowBookmarkBar)) {
     NotificationService::current()->Notify(
         NotificationType::BOOKMARK_BAR_VISIBILITY_PREF_CHANGED,
         Source<PreferenceModelAssociator>(this),
         NotificationService::NoDetails());
   }
 }
 
 }  // namespace browser_sync