ProcessSingleton now uses base::win::MessageWindow to create a message-only window.

chrome/browser/chrome_process_finder_win.cc

 // Copyright 2013 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.
 
 #include "chrome/browser/chrome_process_finder_win.h"
 
 #include <shellapi.h>
 #include <string>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/process_info.h"
 #include "base/process_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/win/message_window.h"
 #include "base/win/metro.h"
 #include "base/win/scoped_handle.h"
 #include "base/win/win_util.h"
 #include "base/win/windows_version.h"
 #include "chrome/browser/metro_utils/metro_chrome_win.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 
 
 namespace {
@@ skipping 57 matching lines @@
   0xffffffffL, 0xfc00987dL, 0x78000001L, 0xb8000001L,
   0xffffffffL, 0xffffffffL, 0xffffffffL, 0xffffffffL
 }};
 
 std::string EscapeQueryParamValue(const std::string& text, bool use_plus) {
   return Escape(text, kQueryCharmap, use_plus);
 }
 
 // END COPY from net/base/escape.cc
 
-}
+}  // namespace
 
 namespace chrome {
 
 HWND FindRunningChromeWindow(const base::FilePath& user_data_dir) {
-  return FindWindowEx(HWND_MESSAGE, NULL, chrome::kMessageWindowClass,
-                      user_data_dir.value().c_str());
+  return base::win::MessageWindow::FindWindow(user_data_dir.value());
 }
 
 NotifyChromeResult AttemptToNotifyRunningChrome(HWND remote_window) {
   DCHECK(remote_window);
   static const char kSearchUrl[] =
       "http://www.google.com/search?q=%s&sourceid=chrome&ie=UTF-8";
   DWORD process_id = 0;
   DWORD thread_id = GetWindowThreadProcessId(remote_window, &process_id);
   if (!thread_id || !process_id)
     return NOTIFY_FAILED;
@@ skipping 69 matching lines @@
 
   // It is possible that the process owning this window may have died by now.
   if (!::IsWindow(remote_window))
     return NOTIFY_FAILED;
 
   // If the window couldn't be notified but still exists, assume it is hung.
   return NOTIFY_WINDOW_HUNG;
 }
 
 }  // namespace chrome