Cleanup vm_service library loading.

runtime/bin/vmservice_impl.h

Index: runtime/bin/vmservice_impl.h
diff --git a/runtime/bin/vmservice_impl.h b/runtime/bin/vmservice_impl.h
index 7d6b08d0007e67856e6229275e053c3bd6045a3a..4769514ea8d0a8eee8beff2a5b4caa5179bba752 100644
--- a/runtime/bin/vmservice_impl.h
+++ b/runtime/bin/vmservice_impl.h
@@ -31,6 +31,7 @@ class VmService {
  private:
   static bool _Start(intptr_t server_port);
   static void _Stop();
+  static Dart_Handle GetSource(const char* name);
   static Dart_Handle LoadScript(const char* name);
   static Dart_Handle LoadSources(Dart_Handle library, const char** names);
   static Dart_Handle LoadSource(Dart_Handle library, const char* name);
@@ -38,6 +39,9 @@ class VmService {
   static Dart_Handle LoadResource(Dart_Handle library, const char* name,
                                   const char* prefix);
 
+  static Dart_Handle LibraryTagHandler(Dart_LibraryTag tag, Dart_Handle library,
+                                       Dart_Handle url);
+
   static void ThreadMain(uword parameters);
 
   static Dart_Isolate isolate_;