Check for duplicate library names

lib/src/codegen/html_codegen.dart

Index: lib/src/codegen/html_codegen.dart
diff --git a/lib/src/codegen/html_codegen.dart b/lib/src/codegen/html_codegen.dart
index 890646ede99c0aee5f98361141b300447b054d3a..2f1908b42ee5b6aab180af711ee10c8c99131814 100644
--- a/lib/src/codegen/html_codegen.dart
+++ b/lib/src/codegen/html_codegen.dart
@@ -13,7 +13,7 @@ import 'package:dev_compiler/src/dependency_graph.dart';
 import 'package:dev_compiler/src/options.dart';
 import 'package:dev_compiler/src/utils.dart' show colorOf, resourceOutputPath;
 
-import 'js_codegen.dart' show jsLibraryName, jsOutputPath;
+import 'js_codegen.dart' show jsOutputPath, jsOutputBase;
 
 /// Emits an entry point HTML file corresponding to [inputFile] that can load
 /// the code generated by the dev compiler.
@@ -82,8 +82,8 @@ String generateEntryHtml(HtmlSourceNode root, CompilerOptions options) {
   for (var lib in libraries) {
     var info = lib.info;
     if (info == null) continue;
-    if (info.isEntry) mainLibraryName = jsLibraryName(info.library);
-    var jsPath = jsOutputPath(info, root.uri);
+    var jsPath = jsOutputPath(info.library, root.uri);
+    if (info.isEntry) mainLibraryName = jsOutputBase(info.library, root.uri);
     if (lib.cachingHash != null) {
       jsPath = _addHash(jsPath, lib.cachingHash);
     }
@@ -104,7 +104,7 @@ Node _invokeMain(String mainLibraryName) {
       ? 'console.error("dev_compiler error: main was not generated");'
       // TODO(vsm): Can we simplify this?
       // See: https://github.com/dart-lang/dev_compiler/issues/164
-      : '_isolate_helper.startRootIsolate($mainLibraryName.main, []);';
+      : "dart.start('$mainLibraryName');";
   return parseFragment('<script>$code</script>\n');
 }