Dart: Renames dart:mojo_blah -> mojo:blah

mojo/dart/test/validation_test.dart

Index: mojo/dart/test/validation_test.dart
diff --git a/mojo/dart/test/validation_test.dart b/mojo/dart/test/validation_test.dart
index 390a63f61208563dfdb6b9ccfc713150bba02b6a..b16f90c55996718b32f37ecaa15b8e1278bb950b 100644
--- a/mojo/dart/test/validation_test.dart
+++ b/mojo/dart/test/validation_test.dart
@@ -5,10 +5,10 @@
 import 'dart:async';
 import 'dart:convert';
 import 'dart:isolate';
-import 'dart:mojo_bindings';
-import 'dart:mojo_builtin' as builtin;
-import 'dart:mojo_core';
 import 'dart:typed_data';
+import 'mojo:bindings';
+import 'mojo:builtin' as builtin;
+import 'mojo:core';
 
 import 'package:mojo/dart/testing/validation_test_input_parser.dart' as parser;
 import 'package:mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom.dart';