Code review fixes.

include/engine/datafacade/datafacade_base.hpp

@@ -192,7 +192,7 @@ class BaseDataFacade
 
     virtual bool IsLeftHandDriving(const NodeID id) const = 0;
 
-    virtual bool IsSegregated(const NodeID) const { return false; }
+    virtual bool IsSegregated(const NodeID) const = 0;
 };
 }
 }

include/engine/guidance/route_step.hpp

@@ -165,8 +165,6 @@ inline RouteStep &RouteStep::ElongateBy(const RouteStep &following_step)
                          following_step.intersections.begin(),
                          following_step.intersections.end());
 
-    /// @todo Process is_segregated flag
-
     return *this;
 }