Don't crash when importing a 404

sky/engine/bindings/core/v8/ScriptController.cpp

 /*
  * Copyright (C) 2008, 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
@@ skipping 335 matching lines @@
 
     V8ScriptModule module;
     module.receiver = toV8(&document, context->Global(), m_isolate);
 
     if (HTMLImport* parent = document.import()) {
         for (HTMLImport* child = parent->firstChild(); child; child = child->next()) {
             if (HTMLLinkElement* link = static_cast<HTMLImportChild*>(child)->link()) {
                 String name = link->as();
                 if (!name.isEmpty()) {
                     module.formalDependenciesAndSource.append(v8String(m_isolate, name));
-                    module.resolvedDependencies.append(child->document() ? child->document()->exports().v8Value() : v8Undefined());
+                    v8::Handle<v8::Value> actual = v8::Undefined(m_isolate);
+                    if (child->document())
+                        actual = child->document()->exports().v8Value();
+                    module.resolvedDependencies.append(actual);
                 }
             }
         }
     }
 
     module.formalDependenciesAndSource.append(v8String(m_isolate, source));
     V8ScriptRunner::runModule(m_isolate, m_frame->document(), module);
 }
 
 } // namespace blink