Avoid manual object's body traversal in GC.

src/heap/objects-visiting.cc

Index: src/heap/objects-visiting.cc
diff --git a/src/heap/objects-visiting.cc b/src/heap/objects-visiting.cc
index 3d6cb7309553ce5d1336a41ab83d2e27f88875c2..fef22f924c02b60c3c84493393673f73f41c40d0 100644
--- a/src/heap/objects-visiting.cc
+++ b/src/heap/objects-visiting.cc
@@ -226,16 +226,18 @@ void HeapObject::IterateBody(InstanceType type, int object_size,
     case JS_SET_ITERATOR_TYPE:
     case JS_MAP_ITERATOR_TYPE:
     case JS_ITERATOR_RESULT_TYPE:
-    case JS_WEAK_MAP_TYPE:
-    case JS_WEAK_SET_TYPE:
     case JS_REGEXP_TYPE:
     case JS_GLOBAL_PROXY_TYPE:
     case JS_GLOBAL_OBJECT_TYPE:
     case JS_MESSAGE_OBJECT_TYPE:
       JSObject::BodyDescriptor::IterateBody(this, object_size, v);
       break;
+    case JS_WEAK_MAP_TYPE:
+    case JS_WEAK_SET_TYPE:
+      JSWeakCollection::BodyDescriptor::IterateBody(this, object_size, v);
+      break;
     case JS_ARRAY_BUFFER_TYPE:
-      JSArrayBuffer::JSArrayBufferIterateBody(this, v);
+      JSArrayBuffer::BodyDescriptor::IterateBody(this, object_size, v);
       break;
     case JS_FUNCTION_TYPE:
       JSFunction::BodyDescriptor::IterateBody(this, object_size, v);
@@ -282,10 +284,9 @@ void HeapObject::IterateBody(InstanceType type, int object_size,
     case FREE_SPACE_TYPE:
       break;
 
-#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
-  case FIXED_##TYPE##_ARRAY_TYPE:                       \
-    reinterpret_cast<FixedTypedArrayBase*>(this)        \
-        ->FixedTypedArrayBaseIterateBody(v);            \
+#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size)                     \
+  case FIXED_##TYPE##_ARRAY_TYPE:                                           \
+    FixedTypedArrayBase::BodyDescriptor::IterateBody(this, object_size, v); \
     break;
       TYPED_ARRAYS(TYPED_ARRAY_CASE)
 #undef TYPED_ARRAY_CASE