[heap] Fix IterateBlackObject for fixed arrays in large object space

BUG=chromium:598319
LOG=N

Review-Url: https://codereview.chromium.org/1943733003
Cr-Commit-Position: refs/heads/master@{#35996}

src/heap/incremental-marking.cc

@@ -277,6 +277,11 @@ class IncrementalMarkingMarkingVisitor
 
 void IncrementalMarking::IterateBlackObject(HeapObject* object) {
   if (IsMarking() && Marking::IsBlack(Marking::MarkBitFrom(object))) {
+    Page* page = Page::FromAddress(object->address());
+    if ((page->owner() != nullptr) && (page->owner()->identity() == LO_SPACE)) {
+      // IterateBlackObject requires us to visit the hole object.
+      page->ResetProgressBar();
+    }
     IncrementalMarkingMarkingVisitor::IterateBody(object->map(), object);
   }
 }