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"
+
+// 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() : override_set_by_current_process_(false) {}
+
+  // 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.
+  // Returns false on unexpected failure.
+  bool SetRegistryOverride();

[robertshield, 2013/04/26 19:20:53]

If I am reading this correctly, a caller should never call both
SetRegistryOverride and StartRegistryOverrideIfNeeded, right? If true, could
that be DCHECKed against somehow (possibly DCHECK(!override_active_))?

[gab, 2013/04/29 02:00:43]

Changed the interface quite a bit, let me know if it makes sense now?

Basically, it's ok for the same process to call both (although it doesn't make
much sense to call StartRegistryOverrideIfNeeded() if you know you called
SetRegistryOverride(), but if you're not sure it doesn't hurt (i.e. the
in-process importer will do this until the OOP import CL is checked in)).

+
+  // 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.
+  // Returns false on unexpected failure.
+  bool StartRegistryOverride();
+
+  // Whether a registry override was initiated in the current process.
+  bool override_active_;

[robertshield, 2013/04/26 19:20:53]

should this be static?

[gab, 2013/04/29 02:00:43]

See main comment.

+
+  // Wheter this process is the one that set the override (and thus should be

[robertshield, 2013/04/26 19:20:53]

nit: Whether

[gab, 2013/04/29 02:00:43]

Done.

+  // the one deleting the temporary key when done).
+  bool override_set_by_current_process_;
+
+  DISALLOW_COPY_AND_ASSIGN(IEImporterTestRegistryOverrider);
+};
+
+#endif  // CHROME_BROWSER_IMPORTER_IE_IMPORTER_TEST_REGISTRY_OVERRIDER_WIN_H_