[heap] Enforce explicit MarkingState

src/heap/array-buffer-tracker.cc

Index: src/heap/array-buffer-tracker.cc
diff --git a/src/heap/array-buffer-tracker.cc b/src/heap/array-buffer-tracker.cc
index d7bbb941e2ca726985863a284fbf4129d97bc1af..c4ad3ba2c771057211a152f376524cc7e2bbdc09 100644
--- a/src/heap/array-buffer-tracker.cc
+++ b/src/heap/array-buffer-tracker.cc
@@ -19,7 +19,10 @@ void LocalArrayBufferTracker::Free() {
   for (TrackingData::iterator it = array_buffers_.begin();
        it != array_buffers_.end();) {
     JSArrayBuffer* buffer = reinterpret_cast<JSArrayBuffer*>(it->first);
-    if ((free_mode == kFreeAll) || ObjectMarking::IsWhite(buffer)) {
+    // TODO(mlippautz): Create a dependency on the collector to avoid getting
+    // the marking state out of thin air.
+    if ((free_mode == kFreeAll) ||
+        ObjectMarking::IsWhite(buffer, MarkingState::Internal(buffer))) {
       const size_t len = it->second;
       heap_->isolate()->array_buffer_allocator()->Free(buffer->backing_store(),
                                                        len);