isolates refactor: this change introduces 'dart:isolate' as a library. This is a

runtime/vm/dart_entry.cc

Index: runtime/vm/dart_entry.cc
diff --git a/runtime/vm/dart_entry.cc b/runtime/vm/dart_entry.cc
index 8ed73accba798e76a3f83e57b92fb2b2a6f80286..51956cef834fe451ec691be4aa06c64155e2558b 100644
--- a/runtime/vm/dart_entry.cc
+++ b/runtime/vm/dart_entry.cc
@@ -202,14 +202,16 @@ RawObject* DartLibraryCalls::Equals(const Instance& left,
 RawObject* DartLibraryCalls::HandleMessage(Dart_Port dest_port_id,
                                            Dart_Port reply_port_id,
                                            const Instance& message) {
+  Library& isolate_lib = Library::Handle(Library::IsolateLibrary());
+  ASSERT(!isolate_lib.IsNull());
   const String& class_name =
-      String::Handle(String::NewSymbol("ReceivePortImpl"));
+      String::Handle(isolate_lib.PrivateName("_ReceivePortImpl"));
   const String& function_name =
       String::Handle(String::NewSymbol("_handleMessage"));
   const int kNumArguments = 3;
   const Array& kNoArgumentNames = Array::Handle();
   const Function& function = Function::Handle(
-      Resolver::ResolveStatic(Library::Handle(Library::CoreLibrary()),
+      Resolver::ResolveStatic(isolate_lib,
                               class_name,
                               function_name,
                               kNumArguments,