Change js_emitter parts into libraries

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

Index: pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
diff --git a/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart b/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
index 362c6c3d54b9589d422cef179388d6430cba2bbe..ecb0ede8f76736b1bb640c7ef77debc75673cbcd 100644
--- a/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
+++ b/pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart
@@ -2,7 +2,42 @@
 // 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.runtime_type_generator;
+
+import '../closure.dart'
+    show ClosureClassMap, ClosureFieldElement;
+import '../common.dart';
+import '../common/names.dart' show Identifiers;
+import '../compiler.dart' show Compiler;
+import '../core_types.dart' show CommonElements;
+import '../elements/resolution_types.dart'
+    show
+    ResolutionDartType,
+    ResolutionFunctionType,
+    ResolutionTypeVariableType;
+import '../elements/elements.dart'
+    show
+    ClassElement,
+    Element,
+    FunctionElement,
+    MixinApplicationElement,
+    TypeVariableElement;
+import '../js/js.dart' as jsAst;
+import '../js/js.dart' show js;
+import '../js_backend/js_backend.dart'
+    show
+    JavaScriptBackend,
+    Namer,
+    RuntimeTypes,
+    RuntimeTypesEncoder,
+    Substitution,
+    TypeCheck,
+    TypeChecks;
+import '../util/util.dart' show Setlet;
+
+import 'code_emitter_task.dart' show CodeEmitterTask;
+import 'model.dart';
+import 'type_test_registry.dart' show TypeTestRegistry;
 
 // Function signatures used in the generation of runtime type information.
 typedef void FunctionTypeSignatureEmitter(