Unify LookupIterator::GetRoot and Objects::GetRootMap

BUG=none
R=verwaest@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/388193002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22369 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/lookup.cc

@@ -22,21 +22,10 @@ void LookupIterator::Next() {
 Handle<JSReceiver> LookupIterator::GetRoot() const {
   Handle<Object> receiver = GetReceiver();
   if (receiver->IsJSReceiver()) return Handle<JSReceiver>::cast(receiver);
-  Context* native_context = isolate_->context()->native_context();
-  JSFunction* function;
-  if (receiver->IsNumber()) {
-    function = native_context->number_function();
-  } else if (receiver->IsString()) {
-    function = native_context->string_function();
-  } else if (receiver->IsSymbol()) {
-    function = native_context->symbol_function();
-  } else if (receiver->IsBoolean()) {
-    function = native_context->boolean_function();
-  } else {
-    UNREACHABLE();
-    function = NULL;
-  }
-  return handle(JSReceiver::cast(function->instance_prototype()));
+  Handle<Object> root =
+      handle(receiver->GetRootMap(isolate_)->prototype(), isolate_);
+  CHECK(!root->IsNull());
+  return Handle<JSReceiver>::cast(root);
 }
 
 

src/objects.h

@@ -1570,6 +1570,7 @@ class Object {
 #endif
 
  private:
+  friend class LookupIterator;
   friend class PrototypeIterator;
 
   // Return the map of the root of object's prototype chain.