[Sync] Add CoreTypes support

sync/syncable/model_type.cc

Index: sync/syncable/model_type.cc
diff --git a/sync/syncable/model_type.cc b/sync/syncable/model_type.cc
index 5e227948b71d9a6b3566b3085ea147a7554f6a54..443b89631a27ba6fa8cec272ed33c1c555a30017 100644
--- a/sync/syncable/model_type.cc
+++ b/sync/syncable/model_type.cc
@@ -367,7 +367,7 @@ ModelTypeSet EncryptableUserTypes() {
   encryptable_user_types.Remove(SYNCED_NOTIFICATIONS);
   // Priority preferences are not encrypted because they might be synced before
   // encryption is ready.
-  encryptable_user_types.RemoveAll(PriorityUserTypes());
+  encryptable_user_types.Remove(PRIORITY_PREFERENCES);
   // Managed user settings are not encrypted since they are set server-side.
   encryptable_user_types.Remove(MANAGED_USER_SETTINGS);
   // Managed users are not encrypted since they are managed server-side.
@@ -380,7 +380,7 @@ ModelTypeSet EncryptableUserTypes() {
 }
 
 ModelTypeSet PriorityUserTypes() {
-  return ModelTypeSet(PRIORITY_PREFERENCES, MANAGED_USERS);
+  return ModelTypeSet(PRIORITY_PREFERENCES);
 }
 
 ModelTypeSet ControlTypes() {
@@ -405,6 +405,18 @@ bool IsControlType(ModelType model_type) {
   return ControlTypes().Has(model_type);
 }
 
+ModelTypeSet PriorityCoreTypes() {
+  syncer::ModelTypeSet result;
+  result.Put(MANAGED_USERS);

[tim (not reviewing), 2013/07/16 16:54:55]

MANAGED_USER_SETTINGS fits the core type definition, but possibly not
priority...

[Nicolas Zea, 2013/07/17 21:05:37]

I don't think it's a core type either? We weren't configuring with it previously
at least.

+  return result;
+}
+
+ModelTypeSet CoreTypes() {

[tim (not reviewing), 2013/07/16 16:54:55]

Should this include PriorityCoreTypes?  What if I want 'all' CoreTypes (which we
do in DTM)?

[Nicolas Zea, 2013/07/17 21:05:37]

Yeah, I suppose CoreTypes() makes more sense as the union. Done.

+  syncer::ModelTypeSet result;
+  result.Put(SYNCED_NOTIFICATIONS);
+  return result;
+}
+
 const char* ModelTypeToString(ModelType model_type) {
   // This is used in serialization routines as well as for displaying debug
   // information.  Do not attempt to change these string values unless you know