Make URLDataSource::GetSource() const.

chrome/browser/printing/cloud_print/cloud_print_setup_source.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_BROWSER_PRINTING_CLOUD_PRINT_CLOUD_PRINT_SETUP_SOURCE_H_
 #define CHROME_BROWSER_PRINTING_CLOUD_PRINT_CLOUD_PRINT_SETUP_SOURCE_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "content/public/browser/url_data_source.h"
 
 class CloudPrintSetupSource : public content::URLDataSource {
  public:
   CloudPrintSetupSource();
 
   // content::URLDataSource implementation.
-  virtual std::string GetSource() OVERRIDE;
+  virtual std::string GetSource() const OVERRIDE;
   virtual void StartDataRequest(
       const std::string& path,
       bool is_incognito,
       const content::URLDataSource::GotDataCallback& callback) OVERRIDE;
   virtual std::string GetMimeType(const std::string& path) const OVERRIDE;
   virtual bool ShouldAddContentSecurityPolicy() const OVERRIDE;
 
   static const char kInvalidPasswordHelpUrl[];
   static const char kCanNotAccessAccountUrl[];
   static const char kCreateNewAccountUrl[];
 
  private:
   virtual ~CloudPrintSetupSource() {}
 
   // Takes a string containing an URL and returns an URL containing a CGI
   // parameter of the form "&hl=xy" where 'xy' is the language code of the
   // current locale.
   std::string GetLocalizedUrl(const std::string& url) const;
 
   DISALLOW_COPY_AND_ASSIGN(CloudPrintSetupSource);
 };
 
 #endif  // CHROME_BROWSER_PRINTING_CLOUD_PRINT_CLOUD_PRINT_SETUP_SOURCE_H_