Don't load dependencies' useless transformers.

sdk/lib/_internal/pub/test/transformers_needed_by_transformers/dev_transformers_test.dart

Index: sdk/lib/_internal/pub/test/transformers_needed_by_transformers/dev_transformers_test.dart
diff --git a/sdk/lib/_internal/pub/test/transformers_needed_by_transformers/dev_transformers_test.dart b/sdk/lib/_internal/pub/test/transformers_needed_by_transformers/dev_transformers_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..f3607be23521c0da372fe650371c7b1447defadc
--- /dev/null
+++ b/sdk/lib/_internal/pub/test/transformers_needed_by_transformers/dev_transformers_test.dart
@@ -0,0 +1,73 @@
+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+library pub_tests;
+
+import 'package:scheduled_test/scheduled_test.dart';
+
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import 'utils.dart';
+
+void main() {
+  initConfig();
+
+  integration("doesn't return a dependency's transformer that can't run on lib",
+      () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "dependencies": {"foo": {"path": "../foo"}}
+      })
+    ]).create();
+
+    d.dir("foo", [
+      d.pubspec({
+        "name": "foo",
+        "version": "1.0.0",
+        "transformers": [{"foo": {"\$include": "test/foo_test.dart"}}]
+      }),
+      d.dir("lib", [d.file("foo.dart", transformer())]),
+      d.dir("test", [d.file("foo_test.dart", "")])
+    ]).create();
+
+    expectDependencies({});
+  });
+
+  integration("does return the root package's transformer that can't run on "
+      "lib", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "transformers": [{"myapp": {"\$include": "test/myapp_test.dart"}}]
+      }),
+      d.dir("lib", [d.file("myapp.dart", transformer())]),
+      d.dir("test", [d.file("myapp_test.dart", "")])
+    ]).create();
+
+    expectDependencies({"myapp": []});
+  });
+
+  integration("doesn't return a dependency's transformer that can run on bin",
+      () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "dependencies": {"foo": {"path": "../foo"}}
+      })
+    ]).create();
+
+    d.dir("foo", [
+      d.pubspec({
+        "name": "foo",
+        "version": "1.0.0",
+        "transformers": [{"foo": {"\$include": "bin/foo.dart"}}]
+      }),
+      d.dir("lib", [d.file("foo.dart", transformer())]),
+      d.dir("test", [d.file("foo_test.dart", "")])
+    ]).create();
+
+    expectDependencies({"foo": []});
+  });
+}