Support dart2js in pub serve.

sdk/lib/_internal/pub/test/transformer/dart2js/ignores_entrypoint_in_dependency_test.dart

Index: sdk/lib/_internal/pub/test/transformer/dart2js/ignores_entrypoint_in_dependency_test.dart
diff --git a/sdk/lib/_internal/pub/test/serve/installs_first_if_dependency_added_test.dart b/sdk/lib/_internal/pub/test/transformer/dart2js/ignores_entrypoint_in_dependency_test.dart
similarity index 56%
copy from sdk/lib/_internal/pub/test/serve/installs_first_if_dependency_added_test.dart
copy to sdk/lib/_internal/pub/test/transformer/dart2js/ignores_entrypoint_in_dependency_test.dart
index c0fde59a3e196263adb7a7cdb98be56767941b91..10aa1c2b1670af34191304371a5455eebbb30c79 100644
--- a/sdk/lib/_internal/pub/test/serve/installs_first_if_dependency_added_test.dart
+++ b/sdk/lib/_internal/pub/test/transformer/dart2js/ignores_entrypoint_in_dependency_test.dart
@@ -4,25 +4,20 @@
 
 library pub_tests;
 
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-import 'utils.dart';
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+import '../../serve/utils.dart';
 
 main() {
   initConfig();
-  integration("installs first if a dependency is not in the lock file", () {
+  integration("ignores a Dart entrypoint in a dependency", () {
     d.dir("foo", [
       d.libPubspec("foo", "0.0.1"),
-      d.libDir("foo")
+      d.dir("lib", [
+        d.file("lib.dart", "main() => print('foo');")
+      ])
     ]).create();
 
-    // Create a lock file without "foo".
-    d.dir(appPath, [
-      d.appPubspec()
-    ]).create();
-    pubInstall();
-
-    // Add it to the pubspec.
     d.dir(appPath, [
       d.appPubspec({
         "foo": {"path": "../foo"}
@@ -30,7 +25,7 @@ main() {
     ]).create();
 
     startPubServe(shouldInstallFirst: true);
-    requestShouldSucceed("packages/foo/foo.dart", 'main() => "foo";');
+    requestShould404("web/packages/foo/lib.dart.js");
     endPubServe();
   });
 }