Reduce service isolate startup time from ~80ms to ~30ms

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 8c9f011040b3a1b2327adbd8ab8f033e0b8c4e46..75457463c391f2349e803126542f28f3a93cc4ff 100644
--- a/runtime/bin/vmservice_impl.h
+++ b/runtime/bin/vmservice_impl.h
@@ -29,6 +29,9 @@ class VmService {
                                   const char* prefix);
   static Dart_Handle LibraryTagHandler(Dart_LibraryTag tag, Dart_Handle library,
                                        Dart_Handle url);
+
+  friend void TriggerResourceLoad(Dart_NativeArguments args);
+
   static void ThreadMain(uword parameters);
   static const char* error_msg_;
   DISALLOW_ALLOCATION();