Fix to respect `@optionalTypeArgs` (#196).

test/rules/always_specify_types.dart

 // Copyright (c) 2015, 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.
 
+
+// Hack to work around issues importing `meta.dart` in tests.
+// Ideally, remove:
+library meta;
+
+class _OptionalTypeArgs {
+  const _OptionalTypeArgs();
+}
+
+const _OptionalTypeArgs optionalTypeArgs = const _OptionalTypeArgs();
+
+// ... and replace w/:
+// import 'package:meta/meta.dart';
+
 List list; // LINT
 List<List> lists; //LINT
 List<int> ints; //OK
 
 final x = 1; //LINT [1:5]
 final int xx = 3;
 const y = 2; //LINT
 const int yy = 3;
 
 a(var x) {} //LINT
 b(s) {} //LINT [3:1]
 c(int x) {}
 d(final x) {} //LINT
 e(final int x) {}
 
+@optionalTypeArgs
+class P<T> { }
+
 main() {
   var x = ''; //LINT [3:3]
   for (var i = 0; i < 10; ++i) {  //LINT [8:3]
     print(i);
   }
   List<String> ls = <String>[];
   ls.forEach((s) => print(s)); //LINT [15:1]
   for (var l in ls) { //LINT [8:3]
     print(l);
   }
   try {
     for (final l in ls) { // LINT [10:5]
       print(l);
     }
   } on Exception catch (ex) {
     print(ex);
   } catch (e) { // NO warning (https://codereview.chromium.org/1427223002/)
     print(e);
   }
 
   var __; // LINT
 
   listen((_) { // OK!
     // ...
   });
+
+  P p = new P(); //OK (optionalTypeArgs)
+}
+
+P doSomething(P p) //OK (optionalTypeArgs)
+{
+  return p;
 }
 
 listen(void onData(Object event)) {}
 
 var z; //LINT
 
 class Foo {
   static var bar; //LINT
   static final baz  = 1; //LINT
   static final int bazz = 42;
   var foo; //LINT
   Foo(var bar); //LINT [7:3]
   void f(List l) { } //LINT
 }