Add Sync datatype for shared managed user settings.

sync/internal_api/public/write_node.h

Index: sync/internal_api/public/write_node.h
diff --git a/sync/internal_api/public/write_node.h b/sync/internal_api/public/write_node.h
index d3781e8b9e10ab10a02f16ae3cc886e15a1f0c05..400ffb7d55a0f99a7e3a3079a197bb4dbcdc6c46 100644
--- a/sync/internal_api/public/write_node.h
+++ b/sync/internal_api/public/write_node.h
@@ -169,6 +169,11 @@ class SYNC_EXPORT WriteNode : public BaseNode {
   // Should only be called if GetModelType() == MANAGED_USERS.
   void SetManagedUserSpecifics(const sync_pb::ManagedUserSpecifics& specifics);
 
+  // Set the managed user shared setting specifics (name and value).
+  // Should only be called if GetModelType() == MANAGED_USER_SHARED_SETTINGS.
+  void SetManagedUserSharedSettingSpecifics(
+      const sync_pb::ManagedUserSharedSettingSpecifics& specifics);
+
   // Set the device info specifics.
   // Should only be called if GetModelType() == DEVICE_INFO.
   void SetDeviceInfoSpecifics(const sync_pb::DeviceInfoSpecifics& specifics);