Update to Chromium //base at Chromium commit 3e81715e6d3a4324362635aea46ce1f1a163cca1.

threading/thread_checker.h

Index: threading/thread_checker.h
diff --git a/threading/thread_checker.h b/threading/thread_checker.h
index 449247af9dd5e56626d65916bd532c120469cef6..1d970f093ed74b4d8f71c8d0c34006a10f171f3f 100644
--- a/threading/thread_checker.h
+++ b/threading/thread_checker.h
@@ -5,23 +5,19 @@
 #ifndef BASE_THREADING_THREAD_CHECKER_H_
 #define BASE_THREADING_THREAD_CHECKER_H_
 
+#include "base/logging.h"
+#include "base/threading/thread_checker_impl.h"
+
 // Apart from debug builds, we also enable the thread checker in
 // builds with DCHECK_ALWAYS_ON so that trybots and waterfall bots
 // with this define will get the same level of thread checking as
 // debug bots.
-//
-// Note that this does not perfectly match situations where DCHECK is
-// enabled.  For example a non-official release build may have
-// DCHECK_ALWAYS_ON undefined (and therefore ThreadChecker would be
-// disabled) but have DCHECKs enabled at runtime.
-#if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
+#if DCHECK_IS_ON()
 #define ENABLE_THREAD_CHECKER 1
 #else
 #define ENABLE_THREAD_CHECKER 0
 #endif
 
-#include "base/threading/thread_checker_impl.h"
-
 namespace base {
 
 // Do nothing implementation, for use in release mode.