Suppress generation of JsGlobal and JsType code and use window as the default value instead of {} f…

lib/src/codegen/js_codegen.dart

Index: lib/src/codegen/js_codegen.dart
diff --git a/lib/src/codegen/js_codegen.dart b/lib/src/codegen/js_codegen.dart
index 6f135f0d21cad9d566835518470bb9e35b167124..e9f0a5d0e1bff103415d6dd826f907cf2bed5fad 100644
--- a/lib/src/codegen/js_codegen.dart
+++ b/lib/src/codegen/js_codegen.dart
@@ -34,6 +34,15 @@ import 'code_generator.dart';
 // This must match the optional parameter name used in runtime.js
 const String _jsNamedParameterName = r'opt$';
 
+bool _isAnnotationType(Annotation m, String name) => m.name.name == name;
+
+Annotation _getAnnotation(AnnotatedNode node, String name) => node.metadata
+    .firstWhere((annotation) => _isAnnotationType(annotation, name),
+        orElse: () => null);
+
+Annotation _getJsNameAnnotation(AnnotatedNode node) =>
+    _getAnnotation(node, "JsName");
+
 class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
   final LibraryInfo libraryInfo;
   final TypeRules rules;
@@ -60,6 +69,19 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
 
   JS.Program generateLibrary(
       Iterable<CompilationUnit> units, CheckerReporter reporter) {
+    var unit = units.first;
+    var jsDefaultValue = '{}';
+    if (unit.directives.isNotEmpty) {
+      var annotation = _getJsNameAnnotation(unit.directives.first);
+      if (annotation != null) {
+        var arguments = annotation.arguments.arguments;
+        if (!arguments.isEmpty) {
+          var namedExpression = arguments.first as NamedExpression;
+          var literal = namedExpression.expression as SimpleStringLiteral;
+          jsDefaultValue = literal.stringValue;
+        }
+      }
+    }
     var body = <JS.Statement>[];
     for (var unit in units) {
       // TODO(jmesserly): this is needed because RestrictedTypeRules can send
@@ -80,10 +102,12 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
     }
 
     var name = jsLibraryName(libraryInfo.library);
+
+    var defaultValue = js.call(jsDefaultValue);
     return new JS.Program([
       js.statement('var #;', name),
-      js.statement("(function($_EXPORTS) { 'use strict'; #; })(# || (# = {}));",
-          [body, name, name])
+      js.statement("(function($_EXPORTS) { 'use strict'; #; })(# || (# = #));",
+          [body, name, name, defaultValue])
     ]);
   }
 
@@ -231,6 +255,8 @@ class JSCodegenVisitor extends GeneralizingAstVisitor with ConversionVisitor {
 
   @override
   JS.Statement visitClassDeclaration(ClassDeclaration node) {
+    if (_getJsNameAnnotation(node) != null) return null;
+
     currentClass = node;
 
     var body = <JS.Statement>[];