Introduce IEImporterTestRegistryOverrider to be able to override the registry for a test and flag t…

chrome/browser/importer/ie_importer_test_registry_overrider_win.h

+// Copyright (c) 2013 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_IMPORTER_IE_IMPORTER_TEST_REGISTRY_OVERRIDER_WIN_H_
+#define CHROME_BROWSER_IMPORTER_IE_IMPORTER_TEST_REGISTRY_OVERRIDER_WIN_H_
+
+#include "base/basictypes.h"
+#include "base/lazy_instance.h"
+#include "base/synchronization/lock.h"
+
+// A helper class to override HKEY_CURRENT_USER to point to a test key from this
+// process' point of view. Also provides functionality (via an environment
+// variable) to let child processes check whether they should also override.
+// Always unsets any existing override upon being deleted.
+class IEImporterTestRegistryOverrider {
+ public:
+  IEImporterTestRegistryOverrider();
+
+  // Unsets any existing registry override and deletes the temporary registry
+  // key if |override_set_by_current_process_|.
+  ~IEImporterTestRegistryOverrider();
+
+  // Calls StartRegistryOverride() and sets an environment variable so that
+  // future calls to StartRegistryOverrideIfNeeded() from child processes also
+  // result in an overriden registry. This method should only be called once

[robertshield, 2013/04/30 03:15:42]

nit: registry -> HKEY_CURRENT_USER hive.

[gab, 2013/04/30 21:44:52]

Done.

+  // across all processes.
+  // Returns false on unexpected failure.
+  bool SetRegistryOverride();
+
+  // Calls StartRegistryOverride() if the environment was set by a parent
+  // process via SetRegistryOverride().
+  // Returns false on unexpected failure.
+  bool StartRegistryOverrideIfNeeded();
+
+ private:
+  // Overrides HKCU to point to a test key from this process' point of view.
+  // Ignored if this process is already overriding the registry.
+  // Returns false on unexpected failure.
+  bool StartRegistryOverride();
+
+  // Returns true if the environment indicates that an override is taking place.
+  bool IsEnvironmentSet();
+
+  // Whether this object started an override for the current process (and thus
+  // should undo it when done).
+  bool in_process_override_started_by_this_;

[robertshield, 2013/04/30 03:15:42]

nit: rename to override_performed_.

[gab, 2013/04/30 21:44:52]

Done.

+
+  // Whether this object is the one that set the override (and thus will be
+  // the one in charge of deleting the temporary key when done).
+  bool override_set_by_this_;

[robertshield, 2013/04/30 03:15:42]

maybe override_initiated_?

[gab, 2013/04/30 21:44:52]

Done.

+
+  // Whether a registry override was initiated in the current process. Accesses
+  // to this variable should only be made while holding |lock_|.
+  static bool override_active_in_process_;
+  static base::LazyInstance<base::Lock>::Leaky lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(IEImporterTestRegistryOverrider);
+};
+
+#endif  // CHROME_BROWSER_IMPORTER_IE_IMPORTER_TEST_REGISTRY_OVERRIDER_WIN_H_