Test RTC_DCHECK_IS_ON instead of checking DCHECK_ALWAYS_ON everywhere

webrtc/base/thread_checker_unittest.cc

Index: webrtc/base/thread_checker_unittest.cc
diff --git a/webrtc/base/thread_checker_unittest.cc b/webrtc/base/thread_checker_unittest.cc
index 2e6afe947beffc16630d88bc90d99b3cb5b69138..87304c89a74385577fd60ea4f49ddcef29227043 100644
--- a/webrtc/base/thread_checker_unittest.cc
+++ b/webrtc/base/thread_checker_unittest.cc
@@ -21,11 +21,7 @@
 
 // Duplicated from base/threading/thread_checker.h so that we can be
 // good citizens there and undef the macro.
-#if !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
-#define ENABLE_THREAD_CHECKER 1
-#else
-#define ENABLE_THREAD_CHECKER 0
-#endif
+#define ENABLE_THREAD_CHECKER (!!RTC_DCHECK_IS_ON)
 
 namespace rtc {