Move EXPECT_DCHECK_DEATH from base/task_scheduler and use it in relevant base/ tests

base/synchronization/cancellation_flag_unittest.cc

Index: base/synchronization/cancellation_flag_unittest.cc
diff --git a/base/synchronization/cancellation_flag_unittest.cc b/base/synchronization/cancellation_flag_unittest.cc
index 13c74bcbd45ffa7b12703e93ab4c5065ccbff88b..0dd63fe9ae32ab3aa9f47aa0464030079ed947c2 100644
--- a/base/synchronization/cancellation_flag_unittest.cc
+++ b/base/synchronization/cancellation_flag_unittest.cc
@@ -8,9 +8,9 @@
 
 #include "base/bind.h"
 #include "base/location.h"
-#include "base/logging.h"
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/spin_wait.h"
+#include "base/test/gtest_util.h"
 #include "base/threading/thread.h"
 #include "base/time/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -20,16 +20,6 @@ namespace base {
 
 namespace {
 
-//------------------------------------------------------------------------------
-// Define our test class.
-//------------------------------------------------------------------------------
-
-void CancelHelper(CancellationFlag* flag) {
-#if GTEST_HAS_DEATH_TEST
-  ASSERT_DEBUG_DEATH(flag->Set(), "");
-#endif
-}
-
 TEST(CancellationFlagTest, SimpleSingleThreadedTest) {
   CancellationFlag flag;
   ASSERT_FALSE(flag.IsSet());
@@ -46,6 +36,10 @@ TEST(CancellationFlagTest, DoubleSetTest) {
   ASSERT_TRUE(flag.IsSet());
 }
 
+void CancelHelper(CancellationFlag* flag) {
+  EXPECT_DCHECK_DEATH(flag->Set(), "");
+}
+
 TEST(CancellationFlagTest, SetOnDifferentThreadDeathTest) {
   // Checks that Set() can't be called from any other thread.
   // CancellationFlag should die on a DCHECK if Set() is called from