Reland of [heap] Simplify marking of JSFunction and SFI

src/heap/objects-visiting-inl.h

Index: src/heap/objects-visiting-inl.h
diff --git a/src/heap/objects-visiting-inl.h b/src/heap/objects-visiting-inl.h
index b8c255e1f399e5e3889d3026ab53fa83a66ffa90..252b2fe5e2fb7b898bc6e21f86981465764b9930 100644
--- a/src/heap/objects-visiting-inl.h
+++ b/src/heap/objects-visiting-inl.h
@@ -449,11 +449,11 @@
       // optimized code.
       collector->code_flusher()->AddCandidate(shared);
       // Treat the reference to the code object weakly.
-      VisitSharedFunctionInfoWeakCode(heap, object);
+      VisitSharedFunctionInfoWeakCode(map, object);
       return;
     }
   }
-  VisitSharedFunctionInfoStrongCode(heap, object);
+  VisitSharedFunctionInfoStrongCode(map, object);
 }
 
 
@@ -621,38 +621,22 @@
   return true;
 }
 
-
 template <typename StaticVisitor>
 void StaticMarkingVisitor<StaticVisitor>::VisitSharedFunctionInfoStrongCode(
-    Heap* heap, HeapObject* object) {
-  Object** start_slot = HeapObject::RawField(
-      object, SharedFunctionInfo::BodyDescriptor::kStartOffset);
-  Object** end_slot = HeapObject::RawField(
-      object, SharedFunctionInfo::BodyDescriptor::kEndOffset);
-  StaticVisitor::VisitPointers(heap, object, start_slot, end_slot);
-}
-
+    Map* map, HeapObject* object) {
+  FixedBodyVisitor<StaticVisitor, SharedFunctionInfo::BodyDescriptor,
+                   void>::Visit(map, object);
+}
 
 template <typename StaticVisitor>
 void StaticMarkingVisitor<StaticVisitor>::VisitSharedFunctionInfoWeakCode(
-    Heap* heap, HeapObject* object) {
-  Object** name_slot =
-      HeapObject::RawField(object, SharedFunctionInfo::kNameOffset);
-  StaticVisitor::VisitPointer(heap, object, name_slot);
-
+    Map* map, HeapObject* object) {
   // Skip visiting kCodeOffset as it is treated weakly here.
-  STATIC_ASSERT(SharedFunctionInfo::kNameOffset + kPointerSize ==
-                SharedFunctionInfo::kCodeOffset);
-  STATIC_ASSERT(SharedFunctionInfo::kCodeOffset + kPointerSize ==
-                SharedFunctionInfo::kOptimizedCodeMapOffset);
-
-  Object** start_slot =
-      HeapObject::RawField(object, SharedFunctionInfo::kOptimizedCodeMapOffset);
-  Object** end_slot = HeapObject::RawField(
-      object, SharedFunctionInfo::BodyDescriptor::kEndOffset);
-  StaticVisitor::VisitPointers(heap, object, start_slot, end_slot);
-}
-
+  STATIC_ASSERT(SharedFunctionInfo::kCodeOffset <
+                SharedFunctionInfo::BodyDescriptorWeakCode::kStartOffset);
+  FixedBodyVisitor<StaticVisitor, SharedFunctionInfo::BodyDescriptorWeakCode,
+                   void>::Visit(map, object);
+}
 
 template <typename StaticVisitor>
 void StaticMarkingVisitor<StaticVisitor>::VisitJSFunctionStrongCode(