Replace deprecated base::NonThreadSafe in base in favor of SequenceChecker.

base/deferred_sequenced_task_runner_unittest.cc

Index: base/deferred_sequenced_task_runner_unittest.cc
diff --git a/base/deferred_sequenced_task_runner_unittest.cc b/base/deferred_sequenced_task_runner_unittest.cc
index 799ddcd13580749b3d89be960843d23dba953d24..a96befacda27eafa8bd44cd7399dda48d71a1fc7 100644
--- a/base/deferred_sequenced_task_runner_unittest.cc
+++ b/base/deferred_sequenced_task_runner_unittest.cc
@@ -11,15 +11,13 @@
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
-#include "base/threading/non_thread_safe.h"
 #include "base/threading/thread.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
 
-class DeferredSequencedTaskRunnerTest : public testing::Test,
-                                        public base::NonThreadSafe {
+class DeferredSequencedTaskRunnerTest : public testing::Test {
  public:
   class ExecuteTaskOnDestructor :
       public base::RefCounted<ExecuteTaskOnDestructor> {