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

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 640ba1e9a33785f03c603015db6984292075796c..e0437f07ae917613d47797cea3b2a9993b8c355b 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -344,13 +344,13 @@ bool Bootstrapper::CreateCodeStubContext(Isolate* isolate) {
   Handle<Context> native_context = CreateEnvironment(
       MaybeHandle<JSGlobalProxy>(), v8::Local<v8::ObjectTemplate>(),
       &no_extensions, THIN_CONTEXT);
-  isolate->heap()->set_code_stub_context(*native_context);
+  isolate->heap()->SetRootCodeStubContext(*native_context);
   isolate->set_context(*native_context);
   Handle<JSObject> code_stub_exports =
       isolate->factory()->NewJSObject(isolate->object_function());
   JSObject::NormalizeProperties(code_stub_exports, CLEAR_INOBJECT_PROPERTIES, 2,
                                 "container to export to extra natives");
-  isolate->heap()->set_code_stub_exports_object(*code_stub_exports);
+  isolate->heap()->SetRootCodeStubExportsObject(*code_stub_exports);
   return InstallCodeStubNatives(isolate);
 }
 
@@ -2173,11 +2173,6 @@ bool Genesis::InstallNatives(ContextType context_type) {
           script_is_embedder_debug_script, attribs);
       script_map->AppendDescriptor(&d);
     }
-
-    // Allocate the empty script.
-    Handle<Script> script = factory()->NewScript(factory()->empty_string());
-    script->set_type(Smi::FromInt(Script::TYPE_NATIVE));
-    heap()->public_set_empty_script(*script);
   }
   {
     // Builtin function for OpaqueReference -- a JSValue-based object,