Add Kernel Isolate

runtime/bin/loader.h

Index: runtime/bin/loader.h
diff --git a/runtime/bin/loader.h b/runtime/bin/loader.h
index 2076be8b3133541462d24ba25d2a29324b25c45e..cc4912dda7011d81d163932caa9249d26fc7c6c8 100644
--- a/runtime/bin/loader.h
+++ b/runtime/bin/loader.h
@@ -93,6 +93,9 @@ class Loader {
                    Dart_Handle url,
                    Dart_Handle library_url);
 
+  // Send a request from the tag handler to the kernel isolate.
+  void SendKernelRequest(Dart_LibraryTag tag, Dart_Handle url);
+
   /// Queue |message| and notify the loader that a message is available.
   void QueueMessage(Dart_CObject* message);