Make URLDataSource::GetSource() const.

chrome/browser/ui/webui/extensions/extension_icon_source.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 CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_ICON_SOURCE_H_
 #define CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_ICON_SOURCE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 53 matching lines @@
                          int icon_size,
                          ExtensionIconSet::MatchType match,
                          bool grayscale,
                          bool* exists);
 
   // A public utility function for accessing the bitmap of the image specified
   // by |resource_id|.
   static SkBitmap* LoadImageByResourceId(int resource_id);
 
   // content::URLDataSource implementation.
-  virtual std::string GetSource() OVERRIDE;
+  virtual std::string GetSource() const OVERRIDE;
   virtual std::string GetMimeType(const std::string&) const OVERRIDE;
   virtual void StartDataRequest(
       const std::string& path,
       bool is_incognito,
       const content::URLDataSource::GotDataCallback& callback) OVERRIDE;
 
  private:
   // Encapsulates the request parameters for |request_id|.
   struct ExtensionIconRequest;
 
@@ skipping 70 matching lines @@
   scoped_ptr<SkBitmap> default_app_data_;
 
   scoped_ptr<SkBitmap> default_extension_data_;
 
   CancelableTaskTracker cancelable_task_tracker_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionIconSource);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_EXTENSIONS_EXTENSION_ICON_SOURCE_H_