When changing Ready Mode state from within an IE process, use chrome_launcher...

chrome_frame/update_launcher.h

+// Copyright (c) 2011 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_FRAME_UPDATE_LAUNCHER_H_
+#define CHROME_FRAME_UPDATE_LAUNCHER_H_
+#pragma once
+
+#include <string>
+
+typedef unsigned long DWORD;  // NOLINT
+
+namespace update_launcher {
+
+// If the command line asks us to run a command via the ProcessLauncher, returns
+// the command ID. Otherwise, returns an empty string.
+std::wstring GetUpdateCommandFromArguments(const wchar_t* command_line);
+
+// Launches the specified command via the ProcessLauncher, waits for the process
+// to exit, and returns the exit code for chrome_launcher (normally the launched
+// command's exit code, or 0xFF in case of failure to launch).
+DWORD LaunchUpdateCommand(const std::wstring& command);
+
+}  // namespace process_launcher
+
+#endif  // CHROME_FRAME_UPDATE_LAUNCHER_H_