Search for a native extension for the host architecture

runtime/bin/extensions.h

Index: runtime/bin/extensions.h
diff --git a/runtime/bin/extensions.h b/runtime/bin/extensions.h
index da18615ba7537b9e131266ed3dabb902d914f5f9..d26630363814eb93c30841a36207e334ddbac9b3 100644
--- a/runtime/bin/extensions.h
+++ b/runtime/bin/extensions.h
@@ -16,7 +16,6 @@ class Extensions {
   // TODO(whesse): Make extension load from a relative path relative to
   // the library it is in.  Currently loads from current working directory.
   static Dart_Handle LoadExtension(const char* extension_directory,
-                                   const char* extension_filename,
                                    const char* extension_name,
                                    Dart_Handle parent_library);