Implement the onBeforeRetarget event of the webNavigation API

chrome/common/render_messages_params.h

 // Copyright (c) 2010 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_COMMON_RENDER_MESSAGES_PARAMS_H_
 #define CHROME_COMMON_RENDER_MESSAGES_PARAMS_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 763 matching lines @@
 
   // Type of window requested.
   WindowContainerType window_container_type;
 
   // The session storage namespace ID this view should use.
   int64 session_storage_namespace_id;
 
   // The name of the resulting frame that should be created (empty if none
   // has been specified).
   string16 frame_name;
+
+  // The frame identifier of the frame initiating the open.
+  int64 opener_frame_id;
+
+  // The URL of the frame initiating the open.
+  GURL opener_url;
+
+  // The URL that will be loaded in the new window (empty if none has been
+  // sepcified).
+  GURL target_url;
 };
 
 struct ViewHostMsg_RunFileChooser_Params {
   enum Mode {
     // Requires that the file exists before allowing the user to pick it.
     Open,
 
     // Like Open, but allows picking multiple files to open.
     OpenMultiple,
 
@@ skipping 341 matching lines @@
 struct ParamTraits<ViewHostMsg_AccessibilityNotification_Params> {
   typedef ViewHostMsg_AccessibilityNotification_Params param_type;
   static void Write(Message* m, const param_type& p);
   static bool Read(const Message* m, void** iter, param_type* p);
   static void Log(const param_type& p, std::string* l);
 };
 
 }  // namespace IPC
 
 #endif  // CHROME_COMMON_RENDER_MESSAGES_PARAMS_H_