Update from https://crrev.com/316786

sandbox/linux/tests/main.cc

 // 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.
 
 #include "base/at_exit.h"
 #include "base/base_switches.h"
 #include "base/command_line.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/test/test_suite.h"
+#include "build/build_config.h"
 #include "sandbox/linux/tests/test_utils.h"
 #include "sandbox/linux/tests/unit_tests.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/multiprocess_func_list.h"
 
 namespace sandbox {
 namespace {
 
 // Check for leaks in our tests.
-void RunPostTestsChecks() {
+void RunPostTestsChecks(const base::FilePath& orig_cwd) {
   if (TestUtils::CurrentProcessHasChildren()) {
-    LOG(ERROR) << "One of the tests created a child that was not waited for. "
-               << "Please, clean-up after your tests!";
+    LOG(FATAL) << "One of the tests created a child that was not waited for. "
+               << "Please, clean up after your tests!";
+  }
+
+  base::FilePath cwd;
+  CHECK(GetCurrentDirectory(&cwd));
+  if (orig_cwd != cwd) {
+    LOG(FATAL) << "One of the tests changed the current working directory. "
+               << "Please, clean up after your tests!";
   }
 }
 
 }  // namespace
 }  // namespace sandbox
 
 #if defined(OS_ANDROID)
 void UnitTestAssertHandler(const std::string& str) {
   _exit(1);
 }
 #endif
 
 int main(int argc, char* argv[]) {
   base::CommandLine::Init(argc, argv);
   std::string client_func =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
           switches::kTestChildProcess);
   if (!client_func.empty()) {
     base::AtExitManager exit_manager;
     return multi_process_function_list::InvokeChildProcessTest(client_func);
   }
 
+  base::FilePath orig_cwd;
+  CHECK(GetCurrentDirectory(&orig_cwd));
+
 #if defined(OS_ANDROID)
   // The use of Callbacks requires an AtExitManager.
   base::AtExitManager exit_manager;
   testing::InitGoogleTest(&argc, argv);
   // Death tests rely on LOG(FATAL) triggering an exit (the default behavior is
   // SIGABRT).  The normal test launcher does this at initialization, but since
   // we still do not use this on Android, we must install the handler ourselves.
   logging::SetLogAssertHandler(UnitTestAssertHandler);
 #endif
   // Always go through re-execution for death tests.
   // This makes gtest only marginally slower for us and has the
   // additional side effect of getting rid of gtest warnings about fork()
   // safety.
   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
 #if defined(OS_ANDROID)
   int tests_result = RUN_ALL_TESTS();
 #else
   int tests_result = base::RunUnitTestsUsingBaseTestSuite(argc, argv);
 #endif
 
-  sandbox::RunPostTestsChecks();
+  sandbox::RunPostTestsChecks(orig_cwd);
   return tests_result;
 }