Handled nullptr argument in WaitForExit() and WaitForExitWithTimeout() methods.

chrome/app/chrome_watcher_client_unittest_win.cc

 // Copyright 2015 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 "chrome/app/chrome_watcher_client_win.h"
 
 #include <windows.h>
 #include <string>
 #include "base/base_switches.h"
 #include "base/bind.h"
@@ skipping 203 matching lines @@
     ASSERT_TRUE(exit_event_.IsValid());
     initialize_event_.Set(::CreateEvent(
         NULL, FALSE, FALSE,
         (kInitializeEventBaseName + thread_.NamedEventSuffix()).c_str()));
     ASSERT_TRUE(initialize_event_.IsValid());
   }
 
   void TearDown() override {
     // Even if we never launched, the following is harmless.
     SignalExit();
-    int exit_code = 0;
-    thread_.client().WaitForExit(&exit_code);
+    thread_.client().WaitForExit(nullptr);
     thread_.Join();
   }
 
  private:
   // Used to launch and block on the Chrome watcher process in a background
   // thread.
   ChromeWatcherClientThread thread_;
   // Used to signal the Chrome watcher process to exit.
   base::win::ScopedHandle exit_event_;
   // Used to signal the Chrome watcher process to signal its own
@@ skipping 25 matching lines @@
   // Give a broken implementation a chance to exit unexpectedly.
   ASSERT_FALSE(thread().WaitForResultWithTimeout(
       base::TimeDelta::FromMilliseconds(100), &result));
   ASSERT_TRUE(SignalExit());
   ASSERT_FALSE(thread().WaitForResult());
   int exit_code = 0;
   ASSERT_TRUE(
       thread().client().WaitForExitWithTimeout(base::TimeDelta(), &exit_code));
   ASSERT_EQ(0, exit_code);
 }