[heap] Limit friendship of the Heap class to essentials.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index e2e5d4dc0bd03f632bcb40655eaaf6b9d64bde84..468aca53ec301e552e2510a2902daaddf5c931c3 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -14107,7 +14107,7 @@ void StringTable::EnsureCapacityForDeserialization(Isolate* isolate,
   // We need a key instance for the virtual hash function.
   InternalizedStringKey dummy_key(Handle<String>::null());
   table = StringTable::EnsureCapacity(table, expected, &dummy_key);
-  isolate->factory()->set_string_table(table);
+  isolate->heap()->SetRootStringTable(*table);
 }
 
 
@@ -14141,7 +14141,7 @@ Handle<String> StringTable::LookupKey(Isolate* isolate, HashTableKey* key) {
   table->set(EntryToIndex(entry), *string);
   table->ElementAdded();
 
-  isolate->factory()->set_string_table(table);
+  isolate->heap()->SetRootStringTable(*table);
   return Handle<String>::cast(string);
 }