Roll Observatory packages and add a roll script

web_components/lib/build/common.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.
-library web_components.build.common;
-
-import 'package:analyzer/analyzer.dart';
-import 'package:barback/barback.dart';
-import 'package:code_transformers/messages/build_logger.dart';
-import 'package:html/dom.dart' as dom;
-import 'package:html/parser.dart';
-import 'package:source_span/source_span.dart';
-import 'package:path/path.dart' as path;
-import 'messages.dart';
-
-/// Generate the import url for a file described by [id], referenced by a file
-/// with [sourceId].
-// TODO(sigmund): this should also be in barback (dartbug.com/12610)
-// TODO(jakemac): This is copied from polymer, we should move it to
-// the code_transformers package so it can be shared.
-String assetUrlFor(AssetId id, AssetId sourceId, BuildLogger logger,
-    {bool allowAssetUrl: false}) {
-  // use package: and asset: urls if possible
-  if (id.path.startsWith('lib/')) {
-    return 'package:${id.package}/${id.path.substring(4)}';
-  }
-
-  if (id.path.startsWith('asset/')) {
-    if (!allowAssetUrl) {
-      logger.error(internalErrorDontKnowHowToImport.create({
-        'target': id,
-        'source': sourceId,
-        'extra': ' (asset urls not allowed.)'
-      }));
-      return null;
-    }
-    return 'asset:${id.package}/${id.path.substring(6)}';
-  }
-
-  // Use relative urls only if it's possible.
-  if (id.package != sourceId.package) {
-    logger.error("don't know how to refer to $id from $sourceId");
-    return null;
-  }
-
-  var builder = path.url;
-  return builder.relative(builder.join('/', id.path),
-      from: builder.join('/', builder.dirname(sourceId.path)));
-}
-
-/// Gets the appropriate URL to use in a span to produce messages (e.g.
-/// warnings) for users. This will attempt to format the URL in the most useful
-/// way:
-///
-/// - If the asset is within the primary package, then use the [id.path],
-///   the user will know it is a file from their own code.
-/// - If the asset is from another package, then use [assetUrlFor], this will
-///   likely be a "package:" url to the file in the other package, which is
-///   enough for users to identify where the error is.
-String spanUrlFor(AssetId id, AssetId sourceId, logger) {
-  bool samePackage = id.package == sourceId.package;
-  return samePackage
-      ? id.path
-      : assetUrlFor(id, sourceId, logger, allowAssetUrl: true);
-}
-
-/// Return the span in a file for an [AstNode].
-FileSpan getSpan(SourceFile file, AstNode node) =>
-    file.span(node.offset, node.end);
-
-/// Parses an HTML file [contents] and returns a DOM-like tree.
-dom.Document parseHtml(String contents, String sourcePath) {
-  var parser = new HtmlParser(contents,
-      encoding: 'utf8', generateSpans: true, sourceUrl: sourcePath);
-  return parser.parse();
-}
-
-const String dartType = "application/dart";
-const String jsType = "text/javascript";