[heap] Avoid redundant size computation in incremental marking.

Change-Id: I91bae96b82078a310b67707f98fb257896e3e00f
Reviewed-on: https://chromium-review.googlesource.com/612083Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47314}

src/heap/incremental-marking.cc

@@ -811,7 +811,7 @@ bool IncrementalMarking::IsFixedArrayWithProgressBar(HeapObject* obj) {
   return chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR);
 }
 
-void IncrementalMarking::VisitObject(Map* map, HeapObject* obj, int size) {
+int IncrementalMarking::VisitObject(Map* map, HeapObject* obj) {
   DCHECK(marking_state()->IsGrey(obj) || marking_state()->IsBlack(obj));
   // The object can already be black in two cases:
   // 1. The object is a fixed array with the progress bar.
@@ -826,7 +826,7 @@ void IncrementalMarking::VisitObject(Map* map, HeapObject* obj, int size) {
   DCHECK(marking_state()->IsBlack(obj));
   WhiteToGreyAndPush(map);
   IncrementalMarkingMarkingVisitor visitor(heap()->mark_compact_collector());
-  visitor.Visit(map, obj);
+  return visitor.Visit(map, obj);
 }
 
 void IncrementalMarking::ProcessBlackAllocatedObject(HeapObject* obj) {
@@ -860,11 +860,8 @@ intptr_t IncrementalMarking::ProcessMarkingWorklist(
       DCHECK(!marking_state()->IsImpossible(obj));
       continue;
     }
-
-    Map* map = obj->map();
-    int size = obj->SizeFromMap(map);
     unscanned_bytes_of_large_object_ = 0;
-    VisitObject(map, obj, size);
+    int size = VisitObject(obj->map(), obj);
     bytes_processed += size - unscanned_bytes_of_large_object_;
   }
   // Report all found wrappers to the embedder. This is necessary as the

src/heap/incremental-marking.h

@@ -311,7 +311,8 @@ class V8_EXPORT_PRIVATE IncrementalMarking {
       ForceCompletionAction completion = DO_NOT_FORCE_COMPLETION));
 
   INLINE(bool IsFixedArrayWithProgressBar(HeapObject* object));
-  INLINE(void VisitObject(Map* map, HeapObject* obj, int size));
+  // Visits the object and returns its size.
+  INLINE(int VisitObject(Map* map, HeapObject* obj));
 
   void RevisitObject(HeapObject* obj);