Add barriers to atomic utils.

test/unittests/atomic-utils-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits.h>
 
 #include "src/atomic-utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace v8 {
@@ skipping 68 matching lines @@
 TEST(AtomicValue, TrySetValue) {
   AtomicValue<TestFlag> a(kA);
   EXPECT_FALSE(a.TrySetValue(kB, kC));
   EXPECT_TRUE(a.TrySetValue(kA, kC));
   EXPECT_EQ(TestFlag::kC, a.Value());
 }
 
 
 TEST(AtomicValue, SetValue) {
   AtomicValue<TestFlag> a(kB);
-  EXPECT_EQ(kB, a.SetValue(kC));
+  a.SetValue(kC);
   EXPECT_EQ(TestFlag::kC, a.Value());
 }
 
 
 TEST(AtomicValue, WithVoidStar) {
   AtomicValue<void*> a(nullptr);
   AtomicValue<void*> dummy(nullptr);
   EXPECT_EQ(nullptr, a.Value());
-  EXPECT_EQ(nullptr, a.SetValue(&a));
+  a.SetValue(&a);
   EXPECT_EQ(&a, a.Value());
   EXPECT_FALSE(a.TrySetValue(nullptr, &dummy));
   EXPECT_TRUE(a.TrySetValue(&a, &dummy));
   EXPECT_EQ(&dummy, a.Value());
 }
 
 
 namespace {
 
 enum TestSetValue { kAA, kBB, kCC, kLastValue = kCC };
@@ skipping 99 matching lines @@
   a.Add(kAA);
   EXPECT_FALSE(a == b);
   EXPECT_TRUE(a != b);
   b.Add(kAA);
   EXPECT_TRUE(a == b);
   EXPECT_FALSE(a != b);
 }
 
 }  // namespace internal
 }  // namespace v8