[modules] Allow resolve-callback to signal failure.

include/v8.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 1077 matching lines @@
    */
   int GetIdentityHash() const;
 
   typedef MaybeLocal<Module> (*ResolveCallback)(Local<Context> context,
                                                 Local<String> specifier,
                                                 Local<Module> referrer);
 
   /**
    * ModuleDeclarationInstantiation
    *
-   * Returns false if an exception occurred during instantiation.
+   * Returns false if an exception occurred during instantiation. (In the case
+   * where the callback throws an exception, that exception is propagated.)
    */
   V8_WARN_UNUSED_RESULT bool Instantiate(Local<Context> context,
                                          ResolveCallback callback);
 
   /**
    * ModuleEvaluation
    *
    * Returns the completion value.
    */
   V8_WARN_UNUSED_RESULT MaybeLocal<Value> Evaluate(Local<Context> context);
@@ skipping 8952 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // INCLUDE_V8_H_