Change EXPECT/ASSERT_DCHECK_DEATH macro to not expose the |regex| parameter.

base/threading/thread_checker_unittest.cc

Index: base/threading/thread_checker_unittest.cc
diff --git a/base/threading/thread_checker_unittest.cc b/base/threading/thread_checker_unittest.cc
index 1b254a1fff29999ce7e8e764e126d9df92ec00f7..10ef2cec44a28655d11805934286e29339086eb6 100644
--- a/base/threading/thread_checker_unittest.cc
+++ b/base/threading/thread_checker_unittest.cc
@@ -125,8 +125,7 @@ void ThreadCheckerClass::MethodOnDifferentThreadImpl() {
 
 #if DCHECK_IS_ON()
 TEST(ThreadCheckerDeathTest, MethodNotAllowedOnDifferentThreadInDebug) {
-  ASSERT_DCHECK_DEATH({ ThreadCheckerClass::MethodOnDifferentThreadImpl(); },
-                      "");
+  ASSERT_DCHECK_DEATH({ ThreadCheckerClass::MethodOnDifferentThreadImpl(); });
 }
 #else
 TEST(ThreadCheckerTest, MethodAllowedOnDifferentThreadInRelease) {
@@ -154,7 +153,7 @@ void ThreadCheckerClass::DetachThenCallFromDifferentThreadImpl() {
 #if DCHECK_IS_ON()
 TEST(ThreadCheckerDeathTest, DetachFromThreadInDebug) {
   ASSERT_DCHECK_DEATH(
-      { ThreadCheckerClass::DetachThenCallFromDifferentThreadImpl(); }, "");
+      { ThreadCheckerClass::DetachThenCallFromDifferentThreadImpl(); });
 }
 #else
 TEST(ThreadCheckerTest, DetachFromThreadInRelease) {