Split dart:builtin into dart:builtin and dart:io.

runtime/bin/builtin_natives.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/builtin.h"
 
 #include <stdlib.h>
 #include <string.h>
 
 #include "bin/dartutils.h"
@@ skipping 100 matching lines @@
 }
 
 void FUNCTION_NAME(Exit)(Dart_NativeArguments args) {
   Dart_EnterScope();
   int64_t status = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 0));
   Dart_ExitScope();
   exit(status);
 }
 
 
-void Builtin::SetNativeResolver() {
-  Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
+void Builtin::SetNativeResolver(Builtin::BuiltinLibraryId id) {
+  Dart_Handle url;
+  if (id == Builtin::kBuiltinLibrary) {
+    url = Dart_NewString(DartUtils::kBuiltinLibURL);
+  } else {
+    ASSERT(id == Builtin::kIOLibrary);
+    url = Dart_NewString(DartUtils::kIOLibURL);
+  }
   Dart_Handle builtin_lib = Dart_LookupLibrary(url);
   DART_CHECK_VALID(builtin_lib);
   // Setup the native resolver for built in library functions.
   Dart_Handle result = Dart_SetNativeResolver(builtin_lib, NativeLookup);
   DART_CHECK_VALID(result);
 }