Change js_emitter parts into libraries

pkg/compiler/lib/src/js_emitter/type_test_registry.dart

Index: pkg/compiler/lib/src/js_emitter/type_test_registry.dart
diff --git a/pkg/compiler/lib/src/js_emitter/type_test_registry.dart b/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
index ffd3b55f647104875969e88ae0cf112ffe3a99ac..24bca0bc71b06d985fce1ecd533cacea88370c78 100644
--- a/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
+++ b/pkg/compiler/lib/src/js_emitter/type_test_registry.dart
@@ -2,7 +2,28 @@
 // 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.
 
-part of dart2js.js_emitter;
+library dart2js.js_emitter.type_test_registry;
+
+import '../compiler.dart' show Compiler;
+import '../elements/resolution_types.dart'
+    show
+    ResolutionDartType,
+    ResolutionFunctionType,
+    ResolutionInterfaceType,
+    Types,
+    ResolutionTypeVariableType;
+import '../elements/elements.dart'
+    show
+    ClassElement,
+    Element,
+    ElementKind,
+    FunctionElement;
+import '../js_backend/js_backend.dart'
+    show
+    JavaScriptBackend,
+    RuntimeTypes,
+    TypeChecks;
+import '../world.dart' show ClosedWorld;
 
 class TypeTestRegistry {
   /**