New test infrastructure for producing verbose logs in failing tests.

chrome/test/logging/win/test_log_collector.h

Index: chrome/test/logging/win/test_log_collector.h
diff --git a/chrome/test/logging/win/test_log_collector.h b/chrome/test/logging/win/test_log_collector.h
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+++ b/chrome/test/logging/win/test_log_collector.h
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+// 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 log collector uses Event Tracing for Windows to collect all LOG()
+// events at all levels (including all VLOG levels) from Chrome, Chrome Frame,
+// and the test executable itself for each test into a temporary log file.  At
+// the conclusion of each test, the contents of the log file are regurgitated to
+// stderr iff the test failed.  In any case, the log file is promptly deleted.
+//
+// Test executables that wish to benefit from the collector's features (to
+// produce verbose logs on test failure to aid in diagnosing flaky and/or
+// failing tests, for example) must install the collector via
+// |InstallTestLogCollector| before running tests (via RUN_ALL_TESTS(),
+// TestSuite::Run(), etc).
+
+#ifndef CHROME_TEST_LOGGING_WIN_TEST_LOG_COLLECTOR_H_
+#define CHROME_TEST_LOGGING_WIN_TEST_LOG_COLLECTOR_H_
+#pragma once
+
+namespace testing {
+class UnitTest;
+}
+
+namespace logging_win {
+
+// Installs the test log collector into |unit_test| for its lifetime.
+// (Use testing::UnitTest::GetInstance() to get the process-wide unit test
+// instance.)
+void InstallTestLogCollector(testing::UnitTest* unit_test);
+
+}  // namespace logging_win
+
+#endif  // CHROME_TEST_LOGGING_WIN_TEST_LOG_COLLECTOR_H_