Remove some unneeded uses of wstring.

chrome/test/automation/proxy_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_TEST_AUTOMATION_PROXY_LAUNCHER_H_
 #define CHROME_TEST_AUTOMATION_PROXY_LAUNCHER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 90 matching lines @@
 #endif
 
   // Exits out of browser instance.
   void QuitBrowser();
 
   // Terminates the browser, simulates end of session.
   void TerminateBrowser();
 
   // Check that no processes related to Chrome exist, displaying
   // the given message if any do.
-  void AssertAppNotRunning(const std::wstring& error_message);
+  void AssertAppNotRunning(const std::string& error_message);
 
   // Wait for the browser process to shut down on its own (i.e. as a result of
   // some action that your test has taken). If it has exited within |timeout|,
   // puts the exit code in |exit_code| and returns true.
   bool WaitForBrowserProcessToQuit(int timeout, int* exit_code);
 
   AutomationProxy* automation() const;
 
   // Return the user data directory being used by the browser instance.
   FilePath user_data_dir() const;
@@ skipping 192 matching lines @@
 
  protected:
   std::string channel_id_;      // Channel id of automation proxy.
   bool disconnect_on_failure_;  // True if we disconnect on IPC channel failure.
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AnonymousProxyLauncher);
 };
 
 #endif  // CHROME_TEST_AUTOMATION_PROXY_LAUNCHER_H_