Rename "NoBarrier" memory operations to "Relaxed".

src/heap/spaces.cc

Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index 66e7defe77f6ced0d6994f554ac03c37fe30b98c..3152296af1d9e6f416085a1ffe532209cad6764d 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -2841,7 +2841,7 @@ size_t FreeListCategory::SumFreeList() {
   FreeSpace* cur = top();
   while (cur != NULL) {
     DCHECK(cur->map() == cur->GetHeap()->root(Heap::kFreeSpaceMapRootIndex));
-    sum += cur->nobarrier_size();
+    sum += cur->relaxed_read_size();
     cur = cur->next();
   }
   return sum;