Make URLDataSource::GetSource() const.

content/browser/webui/web_ui_data_source_impl.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_WEBUI_WEB_UI_DATA_SOURCE_IMPL_H_
 #define CONTENT_BROWSER_WEBUI_WEB_UI_DATA_SOURCE_IMPL_H_
 
 #include <map>
 #include <string>
 
@@ skipping 52 matching lines @@
  private:
   class InternalDataSource;
   friend class InternalDataSource;
   friend class WebUIDataSource;
   friend class WebUIDataSourceTest;
 
   explicit WebUIDataSourceImpl(const std::string& source_name);
 
   // Methods that match URLDataSource which are called by
   // InternalDataSource.
-  std::string GetSource();
+  std::string GetSource() const;
   std::string GetMimeType(const std::string& path) const;
   void StartDataRequest(
       const std::string& path,
       bool is_incognito,
       const URLDataSource::GotDataCallback& callback);
 
   void disable_set_font_strings_for_testing() {
     disable_set_font_strings_ = true;
   }
 
@@ skipping 14 matching lines @@
   std::string frame_src_;
   bool deny_xframe_options_;
   bool disable_set_font_strings_;
 
   DISALLOW_COPY_AND_ASSIGN(WebUIDataSourceImpl);
 };
 
 }  // content
 
 #endif  // CONTENT_BROWSER_WEBUI_WEB_UI_DATA_SOURCE_IMPL_H_