Fix cpplint whitespace/blank_line issues

Change-Id: Ice937e95e23dd622c17054551d4ae4cebd0ef8a2
diff --git a/runtime/barrier.cc b/runtime/barrier.cc
index 250d468..a644998 100644
--- a/runtime/barrier.cc
+++ b/runtime/barrier.cc
@@ -60,4 +60,4 @@
   CHECK(!count_) << "Attempted to destroy barrier with non zero count";
 }
 
-}
+}  // namespace art