Fix unhandled promise console message to show stack trace of a DOMException.

Source/bindings/core/v8/V8ThrowException.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 55 matching lines @@
     v8::Handle<v8::Value> exception = toV8(domException, creationContext, isolate);
 
     if (exception.IsEmpty())
         return v8Undefined();
 
     // Attach an Error object to the DOMException. This is then lazily used to get the stack value.
     v8::Handle<v8::Value> error = v8::Exception::Error(v8String(isolate, domException->message()));
     ASSERT(!error.IsEmpty());
     ASSERT(exception->IsObject());
     exception->ToObject()->SetAccessor(v8AtomicString(isolate, "stack"), domExceptionStackGetter, domExceptionStackSetter, error);
+    V8HiddenValue::setHiddenValue(isolate, exception->ToObject(), V8HiddenValue::error(isolate), error);
 
     return exception;
 }
 
 v8::Handle<v8::Value> V8ThrowException::throwDOMException(int ec, const String& sanitizedMessage, const String& unsanitizedMessage, const v8::Handle<v8::Object>& creationContext, v8::Isolate* isolate)
 {
     ASSERT(ec == SecurityError || unsanitizedMessage.isEmpty());
     v8::Handle<v8::Value> exception = createDOMException(ec, sanitizedMessage, unsanitizedMessage, creationContext, isolate);
     if (exception.IsEmpty())
         return v8Undefined();
@@ skipping 57 matching lines @@
 }
 
 v8::Handle<v8::Value> V8ThrowException::throwException(v8::Handle<v8::Value> exception, v8::Isolate* isolate)
 {
     if (!v8::V8::IsExecutionTerminating())
         isolate->ThrowException(exception);
     return v8::Undefined(isolate);
 }
 
 } // namespace blink