Ensure that --disable-extensions disables extension prefs from being enacted

chrome/browser/extensions/test_extension_prefs.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_EXTENSIONS_TEST_EXTENSION_PREFS_H_
 #define CHROME_BROWSER_EXTENSIONS_TEST_EXTENSION_PREFS_H_
 #pragma once
 
 #include <string>
 
@@ skipping 43 matching lines @@
       Extension::Location location,
       int extra_flags);
 
   // Similar to AddExtension, this adds a new test Extension. This is useful for
   // cases when you don't need the Extension object, but just the id it was
   // assigned.
   std::string AddExtensionAndReturnId(std::string name);
 
   PrefService* CreateIncognitoPrefService() const;
 
+  // Allows disabling the loading of preferences of extensions. Becomes
+  // active after calling RecreateExtensionPrefs(). Defaults to false.
+  void set_extensions_disabled(bool extensions_disabled);
+
  protected:
   ScopedTempDir temp_dir_;
   FilePath preferences_file_;
   FilePath extensions_dir_;
   scoped_ptr<PrefService> pref_service_;
   scoped_ptr<ExtensionPrefs> prefs_;
   scoped_ptr<ExtensionPrefValueMap> extension_pref_value_map_;
 
  private:
+  bool extensions_disabled_;
   DISALLOW_COPY_AND_ASSIGN(TestExtensionPrefs);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_TEST_EXTENSION_PREFS_H_