Tidy up memory barriers.

Change-Id: I937ea93e6df1835ecfe2d4bb7d84c24fe7fc097b
diff --git a/runtime/instrumentation.cc b/runtime/instrumentation.cc
index 4ad9c63..47c1899 100644
--- a/runtime/instrumentation.cc
+++ b/runtime/instrumentation.cc
@@ -407,9 +407,9 @@
 void Instrumentation::InstrumentQuickAllocEntryPoints() {
   // TODO: the read of quick_alloc_entry_points_instrumentation_counter_ is racey and this code
   //       should be guarded by a lock.
-  DCHECK_GE(quick_alloc_entry_points_instrumentation_counter_.load(), 0);
+  DCHECK_GE(quick_alloc_entry_points_instrumentation_counter_.Load(), 0);
   const bool enable_instrumentation =
-      quick_alloc_entry_points_instrumentation_counter_.fetch_add(1) == 0;
+      quick_alloc_entry_points_instrumentation_counter_.FetchAndAdd(1) == 0;
   if (enable_instrumentation) {
     // Instrumentation wasn't enabled so enable it.
     SetQuickAllocEntryPointsInstrumented(true);
@@ -420,9 +420,9 @@
 void Instrumentation::UninstrumentQuickAllocEntryPoints() {
   // TODO: the read of quick_alloc_entry_points_instrumentation_counter_ is racey and this code
   //       should be guarded by a lock.
-  DCHECK_GT(quick_alloc_entry_points_instrumentation_counter_.load(), 0);
+  DCHECK_GT(quick_alloc_entry_points_instrumentation_counter_.Load(), 0);
   const bool disable_instrumentation =
-      quick_alloc_entry_points_instrumentation_counter_.fetch_sub(1) == 1;
+      quick_alloc_entry_points_instrumentation_counter_.FetchAndSub(1) == 1;
   if (disable_instrumentation) {
     SetQuickAllocEntryPointsInstrumented(false);
     ResetQuickAllocEntryPoints();