Improves how to initialize polymer apps and fixes polymer build and linter to

pkg/polymer/lib/src/loader.dart

 // Copyright (c) 2013, 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.
 
 part of polymer;
 
 /** Annotation used to automatically register polymer elements. */
 class CustomTag {
   final String tagName;
   const CustomTag(this.tagName);
@@ skipping 14 matching lines @@
  *      [CustomTag] and invoke the initialization method on it. If [libraries]
  *      is null, first find all libraries that need to be loaded by scanning for
  *      HTML imports in the main document.
  *
  * The initialization on each library is a top-level function and annotated with
  * [initMethod].
  *
  * The urls in [libraries] can be absolute or relative to
  * `currentMirrorSystem().isolate.rootLibrary.uri`.
  */
-void initPolymer([List<String> libraries]) {
+void initPolymer() {
   runMicrotask(() {
     // DOM events don't yet go through microtasks, so we catch those here.
     new Timer.periodic(new Duration(milliseconds: 125),
         (_) => performMicrotaskCheckpoint());
 
     preventFlashOfUnstyledContent();
 
     // TODO(jmesserly): mdv should use initMdv instead of mdv.initialize.
     mdv.initialize();
     document.register(PolymerDeclaration._TAG, PolymerDeclaration);
 
     // Note: we synchronously load all libraries because the script invoking
     // this is run after all HTML imports are resolved.
-    if (libraries == null) {
-      libraries = _discoverScripts(document, window.location.href);
-    }
-    _loadLibraries(libraries);
+    _loadLibraries();
   });
 }
 
-void _loadLibraries(libraries) {
-  for (var lib in libraries) {
+List<String> librariesToLoad =
+    _discoverScripts(document, window.location.href);
+
+void _loadLibraries() {
+  for (var lib in librariesToLoad) {
     _loadLibrary(lib);
   }
   Polymer._ready.complete();
 }
 
 /**
  * Walks the HTML import structure to discover all script tags that are
  * implicitly loaded.
  */
 List<String> _discoverScripts(Document doc, String baseUri,
@@ skipping 137 matching lines @@
     print("warning: methods marked with @initMethod should take no "
         "arguments, ${method.simpleName} expects some.");
     return;
   }
   obj.invoke(method.simpleName, const []);
 }
 
 class _InitMethodAnnotation {
   const _InitMethodAnnotation();
 }