Change js_emitter parts into libraries

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

Index: pkg/compiler/lib/src/js_emitter/interceptor_stub_generator.dart
diff --git a/pkg/compiler/lib/src/js_emitter/interceptor_stub_generator.dart b/pkg/compiler/lib/src/js_emitter/interceptor_stub_generator.dart
index d235adb4a0d043e7781d0cc036aee73773803a9a..6218518ee2916cbfdf9152740b683abf7f614ea4 100644
--- a/pkg/compiler/lib/src/js_emitter/interceptor_stub_generator.dart
+++ b/pkg/compiler/lib/src/js_emitter/interceptor_stub_generator.dart
@@ -2,7 +2,31 @@
 // 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.interceptor_stub_generator;
+
+import '../compiler.dart' show Compiler;
+import '../constants/values.dart';
+import '../elements/resolution_types.dart'
+    show
+    ResolutionInterfaceType;
+import '../elements/elements.dart'
+    show
+    ClassElement,
+    Element;
+import '../js/js.dart' as jsAst;
+import '../js/js.dart' show js;
+import '../js_backend/backend_helpers.dart' show BackendHelpers;
+import '../js_backend/js_backend.dart'
+    show
+    CustomElementsAnalysis,
+    JavaScriptBackend,
+    JavaScriptConstantCompiler,
+    Namer;
+import '../universe/selector.dart' show Selector;
+import '../world.dart' show ClosedWorld;
+
+import 'code_emitter_task.dart' show Emitter;
 
 class InterceptorStubGenerator {
   final Compiler compiler;