fix barback and polymer build warnings

pkg/polymer/lib/src/build/import_inliner.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.
 
 /** Transfomer that inlines polymer-element definitions from html imports. */
 library polymer.src.build.import_inliner;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:barback/barback.dart';
 import 'package:path/path.dart' as path;
-import 'package:html5lib/dom.dart' show Document, Node, DocumentFragment;
+import 'package:html5lib/dom.dart' show
+    Document, DocumentFragment, Element, Node;
 import 'package:html5lib/dom_parsing.dart' show TreeVisitor;
+import 'package:source_maps/span.dart' show Span;
 
 import 'code_extractor.dart'; // import just for documentation.
 import 'common.dart';
 
 /**
  * Recursively inlines the contents of HTML imports. Produces as output a single
  * HTML file that inlines the polymer-element definitions, and a text file that
  * contains, in order, the URIs to each library that sourced in a script tag.
  *
  * This transformer assumes that all script tags point to external files. To
@@ skipping 63 matching lines @@
             //TODO(jmesserly): add Node.firstChild to html5lib
             document.body.nodes.length == 0 ? null : document.body.nodes[0]);
         transform.addOutput(new Asset.fromString(id, document.outerHtml));
 
         var scriptIds = [];
         for (var script in scripts) {
           var src = script.attributes['src'];
           if (src == null) {
             logger.warning('unexpected script without a src url. The '
               'ImportInliner transformer should run after running the '
-              'InlineCodeExtractor', script.sourceSpan);
+              'InlineCodeExtractor', span: script.sourceSpan);
             continue;
           }
           scriptIds.add(resolve(id, src, logger, script.sourceSpan));
         }
         transform.addOutput(new Asset.fromString(secondaryId,
             JSON.encode(scriptIds, toEncodable: (id) => id.serialize())));
       });
     });
   }
 
@@ skipping 90 matching lines @@
 
     if (id.path.startsWith('lib/')) {
       return 'packages/${id.package}/${id.path.substring(4)}';
     }
 
     if (id.path.startsWith('asset/')) {
       return 'assets/${id.package}/${id.path.substring(6)}';
     }
 
     if (primaryId.package != id.package) {
       // Techincally we shouldn't get there

[Siggi Cherem (dart-lang), 2013/10/30 01:12:40]

love the irony =)

-      logger.error("don't know how to include $id from $primaryId", span);
+      transform.logger.error("don't know how to include $id from $primaryId",
+          span: span);
       return null;
     }
-    
+
     var builder = path.url;
     return builder.relative(builder.join('/', id.path),
         from: builder.join('/', builder.dirname(primaryId.path)));
   }
 }
 
 /**
  * HTML attributes that expect a URL value.
  * <http://dev.w3.org/html5/spec/section-index.html#attributes-1>
  *
  * Every one of these attributes is a URL in every context where it is used in
  * the DOM. The comments show every DOM element where an attribute can be used.
  */
 const _urlAttributes = const [
   'action',     // in form
   'background', // in body
   'cite',       // in blockquote, del, ins, q
   'data',       // in object
   'formaction', // in button, input
   'href',       // in a, area, link, base, command
   'icon',       // in command
   'manifest',   // in html
   'poster',     // in video
   'src',        // in audio, embed, iframe, img, input, script, source, track,
                 //    video
 ];