text: // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef CHROME_RENDERER_EXTERNAL_HOST_BINDINGS_H_
  #define CHROME_RENDERER_EXTERNAL_HOST_BINDINGS_H_
  
  #include "chrome/common/ipc_message.h"
  #include "chrome/renderer/dom_ui_bindings.h"
  
  // ExternalHostBindings is the class backing the "externalHost" object
  // accessible from Javascript
  //
  // We expose one function, for sending a message to the external host:
  //  postMessage(String message[, String target]);
  class ExternalHostBindings : public DOMBoundBrowserObject {
   public:
    ExternalHostBindings();
    virtual ~ExternalHostBindings() {
    }
  
    // The postMessage() function provided to Javascript.
    void postMessage(const CppArgumentList& args, CppVariant* result);
  
    // Invokes the registered onmessage handler.
    // Returns true on successful invocation.
    bool ForwardMessageFromExternalHost(const std::string& message,
                                        const std::string& origin,
                                        const std::string& target);
  
    // Overridden to hold onto a pointer back to the web frame.
    void BindToJavascript(WebFrame* frame, const std::wstring& classname) {
      frame_ = frame;
      DOMBoundBrowserObject::BindToJavascript(frame, classname);
    }
  
   protected:
    // Creates an uninitialized instance of a MessageEvent object.
    // This is equivalent to calling window.document.createEvent("MessageEvent")
    // in javascript.
    bool CreateMessageEvent(NPObject** message_event);
  
   private:
    CppVariant on_message_handler_;
    WebFrame* frame_;
  
    DISALLOW_COPY_AND_ASSIGN(ExternalHostBindings);
  };
  
  #endif  // CHROME_RENDERER_EXTERNAL_HOST_BINDINGS_H_
  