Convert infobar APIs to UTF-16.

chrome/browser/plugin_installer.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_BROWSER_PLUGIN_INSTALLER_H_
 #define CHROME_BROWSER_PLUGIN_INSTALLER_H_
 #pragma once
 
 #include "chrome/browser/tab_contents/infobar_delegate.h"
 
 class TabContents;
 
 // The main purpose for this class is to popup/close the infobar when there is
 // a missing plugin.
 class PluginInstaller : public ConfirmInfoBarDelegate {
  public:
   explicit PluginInstaller(TabContents* tab_contents);
   ~PluginInstaller();
 
   void OnMissingPluginStatus(int status);
   // A new page starts loading. This is the perfect time to close the info bar.
   void OnStartLoading();
 
  private:
   // Overridden from ConfirmInfoBarDelegate:
-  virtual std::wstring GetMessageText() const;
+  virtual string16 GetMessageText() const;
   virtual SkBitmap* GetIcon() const;
   virtual int GetButtons() const;
-  virtual std::wstring GetButtonLabel(InfoBarButton button) const;
+  virtual string16 GetButtonLabel(InfoBarButton button) const;
   virtual bool Accept();
-  virtual std::wstring GetLinkText();
+  virtual string16 GetLinkText();
   virtual bool LinkClicked(WindowOpenDisposition disposition);
 
   // The containing TabContents
   TabContents* tab_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginInstaller);
 };
 
 #endif  // CHROME_BROWSER_PLUGIN_INSTALLER_H_