Add scoped path overrides for system directories for ExtensionBrowserTests.

chrome/browser/extensions/extension_browsertest.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_EXTENSIONS_EXTENSION_BROWSERTEST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_BROWSERTEST_H_
 
 #include <string>
 
 #include "base/command_line.h"
 
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
+#include "base/test/scoped_path_override.h"
 #include "chrome/browser/extensions/extension_test_notification_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/extensions/features/feature_channel.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "content/public/browser/web_contents.h"
 #include "extensions/browser/extension_host.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/feature_switch.h"
@@ skipping 344 matching lines @@
       bool wait_for_idle,
       bool is_ephemeral);
 
   // Make the current channel "dev" for the duration of the test.
   extensions::ScopedCurrentChannel current_channel_;
 
   // Disable external install UI.
   extensions::FeatureSwitch::ScopedOverride
       override_prompt_for_external_extensions_;
 
+  base::ScopedTempDir fake_user_desktop_;
+  base::ScopedTempDir fake_common_desktop_;
+  base::ScopedTempDir fake_user_quick_launch_;
+  base::ScopedTempDir fake_default_user_quick_launch_;
+  base::ScopedTempDir fake_start_menu_;
+  base::ScopedTempDir fake_common_start_menu_;
+  scoped_ptr<base::ScopedPathOverride> user_desktop_override_;
+  scoped_ptr<base::ScopedPathOverride> common_desktop_override_;
+  scoped_ptr<base::ScopedPathOverride> user_quick_launch_override_;
+  scoped_ptr<base::ScopedPathOverride> start_menu_override_;
+  scoped_ptr<base::ScopedPathOverride> common_start_menu_override_;

[gab, 2014/09/12 13:57:09]

Add a comment explaining why we're mocking those paths.

[gab, 2014/09/12 13:57:09]

Since the tests don't need to reference the paths directly, simply use direct 

base::ScopedPathOverride foo_override_;

members (which will internally use their own ScopedTempDir).

[calamity, 2014/09/15 01:50:28]

Done.

[calamity, 2014/09/15 01:50:28]

Done.

+
   // The default profile to be used.
   Profile* profile_;
 
   // Cache cache implementation.
   scoped_ptr<extensions::ExtensionCacheFake> test_extension_cache_;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_BROWSERTEST_H_