Make NoReloadScope thread safe

runtime/vm/atomic_test.cc

Index: runtime/vm/atomic_test.cc
diff --git a/runtime/vm/atomic_test.cc b/runtime/vm/atomic_test.cc
index 6973d8b42a03c14a8ead95c8ca2e7e1935166d9e..782f4f308fe43445454ddb932e8cfd654de2029b 100644
--- a/runtime/vm/atomic_test.cc
+++ b/runtime/vm/atomic_test.cc
@@ -26,6 +26,22 @@ UNIT_TEST_CASE(FetchAndDecrement) {
 }
 
 
+UNIT_TEST_CASE(FetchAndIncrementSigned) {
+  intptr_t v = -42;
+  EXPECT_EQ(static_cast<uintptr_t>(-42),

[Florian Schneider, 2016/09/16 18:01:36]

intptr_t

[Cutch, 2016/09/16 18:07:51]

Done here and elsewhere.

+            AtomicOperations::FetchAndIncrement(&v));
+  EXPECT_EQ(static_cast<uintptr_t>(-41), v);

[Florian Schneider, 2016/09/16 18:01:36]

intptr_t?

Or remove these static_casts. They seem redundant.

+}
+
+
+UNIT_TEST_CASE(FetchAndDecrementSigned) {
+  intptr_t v = -42;
+  EXPECT_EQ(static_cast<uintptr_t>(-42),

[Florian Schneider, 2016/09/16 18:01:36]

Same as above.

+            AtomicOperations::FetchAndDecrement(&v));
+  EXPECT_EQ(static_cast<uintptr_t>(-43), v);

[Florian Schneider, 2016/09/16 18:01:36]

Same as above.

+}
+
+
 UNIT_TEST_CASE(IncrementBy) {
   intptr_t v = 42;
   AtomicOperations::IncrementBy(&v, 100);