Reduce flakiness in chrome_frame_tests.exe by having each run in a clean environment.

chrome_frame/test/test_scrubber.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.
+
+// The test scrubber cleans up machine state between tests.  This includes
+// killing all Internet Explorer processes, killing all Chrome processes spawned
+// by Chrome Frame, and deleting the user data directory.  The scrubber must be
+// installed before tests are run via |InstallTestScrubber|.
+//
+// Tests that lead to Chrome using a user data directory other than that used by
+// Chrome Frame in IE must provide that directory to the scrubber via
+// |OverrideDataDirectoryForThisTest()|.  Failure to do so will lead to the
+// scrubber failing to delete that directory.  See CFACWithChrome::SetUp in
+// automation_client_mock.cc for an example.

[robertshield, 2012/02/28 03:32:15]

The last sentence is prone to rapid bitrotting (likely to get invalidated if
anyone comes in and tries to refactor this stuff).  I'd remove it (or at least
remove the file name) since the curious can search for usages using technology.

[grt (UTC plus 2), 2012/02/28 04:03:25]

Removed.  I initially changed it to "search for it to see good examples," but
since that's almost universally true of all code (except where it isn't), it
didn't seem to add value.

+
+#ifndef CHROME_FRAME_TEST_TEST_SCRUBBER_H_
+#define CHROME_FRAME_TEST_TEST_SCRUBBER_H_
+#pragma once
+
+#include "base/string_piece.h"
+
+namespace testing {
+class UnitTest;
+}
+
+namespace chrome_frame_test {
+
+// Install the scrubber in |unit_test| (call before RUN_ALL_TESTS).
+void InstallTestScrubber(testing::UnitTest* unit_test);
+
+// Override the user data directory that will be deleted by the scrubber at the
+// completion of the current test.
+void OverrideDataDirectoryForThisTest(const base::StringPiece16& user_data_dir);
+
+}  // namespace chrome_frame_test
+
+#endif  // CHROME_FRAME_TEST_TEST_SCRUBBER_H_