Switch polymer's build.dart to use the new linter. This CL does the following

pkg/polymer/lib/src/barback_helper.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.
+
+/**
+ * Definitions used to run the polymer linter and deploy tools without using
+ * pub serve or pub deploy.
+ */
+library polymer.src.barback_helper;

[Jennifer Messerly, 2013/09/10 04:16:51]

i'm not a huge fan of _helper, could we just call it barback?

[Siggi Cherem (dart-lang), 2013/09/11 01:45:26]

Not sure if that's too confusing. Other ideas:
- utils_barback
- barback_utils
- barback_runner

Currently leaning towards the third one. I did this rename in PatchSet 3
(PatchSet 2 kept this file in place and did all the other fixes).

+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:barback/barback.dart';
+import 'package:path/path.dart' as path;
+import 'package:stack_trace/stack_trace.dart';
+import 'package:yaml/yaml.dart';
+import 'package:args/args.dart';

[Jennifer Messerly, 2013/09/10 04:16:51]

sort if you want :)

[Siggi Cherem (dart-lang), 2013/09/11 01:45:26]

doh. we need an autoformatter... 

+
+
+/** Collects different parameters needed to configure and run barback. */

[Siggi Cherem (dart-lang), 2013/09/10 03:40:57]

this configuration and runBarback are new.

+class BarbackOptions {
+  /** Phases of transformers to run. */
+  final List<List<Transformer>> phases;
+
+  /** Package to treat as the current package in barback. */
+  final String currentPackage;
+
+  /**
+   * Mapping between package names and the path in the file system where
+   * to find the sources of such package.
+   */
+  final Map<String, String> packageDirs;
+
+  /** Whether to run transformers on the test folder. */
+  final bool transformTests;
+
+  /** Whether to apply transformers on polymer dependencies. */
+  final bool transformPolymerDependencies;
+
+  /** Directory where to generate code, if any. */
+  final String outDir;
+
+  BarbackOptions(this.phases, this.outDir, {currentPackage, packageDirs,
+      this.transformTests: false, this.transformPolymerDependencies: false})
+      : currentPackage = (currentPackage != null
+          ? currentPackage : readCurrentPackageFromPubspec()),
+        packageDirs = (packageDirs != null
+          ? packageDirs : _readPackageDirsFromPub(currentPackage));
+
+}
+
+/**
+ * Creates a barback system as specified by [options] and runs it.  Returns a
+ * future that contains the list of assets generated after barback runs to
+ * completion.
+ */
+Future<AssetSet> runBarback(BarbackOptions options) {
+  var barback = new Barback(new _PolymerPackageProvider(options.packageDirs));
+  _initBarback(barback, options);
+  _attachListeners(barback);
+  if (options.outDir == null) return barback.getAllAssets();
+  return _emitAllFiles(barback, options);
+}
+
+/** Extract the current package from the pubspec.yaml file. */
+String readCurrentPackageFromPubspec() {

[Siggi Cherem (dart-lang), 2013/09/10 03:40:57]

the logic here and below is the same as before, with minor tweaks to use the
'options' object where necessary.

+  var pubspec = new File('pubspec.yaml');
+  if (!pubspec.existsSync()) {
+    print('error: pubspec.yaml file not found, please run this script from '
+        'your package root directory.');
+    return null;
+  }
+  return loadYaml(pubspec.readAsStringSync())['name'];
+}
+
+/**
+ * Extract a mapping between package names and the path in the file system where
+ * to find the sources of such package. This map will contain an entry for the
+ * current package and everything it depends on (extracted via `pub
+ * list-pacakge-dirs`).
+ */
+Map<String, String> _readPackageDirsFromPub(String currentPackage) {
+  var dartExec = new Options().executable;
+  // If dartExec == dart, then dart and pub are in standard PATH.
+  var sdkDir = dartExec == 'dart' ? '' : path.dirname(dartExec);
+  var pub = path.join(sdkDir, Platform.isWindows ? 'pub.bat' : 'pub');
+  var result = Process.runSync(pub, ['list-package-dirs']);
+  if (result.exitCode != 0) {
+    print("unexpected error invoking 'pub':");
+    print(result.stdout);
+    print(result.stderr);
+    exit(result.exitCode);
+  }
+  var map = JSON.decode(result.stdout)["packages"];
+  map.forEach((k, v) { map[k] = path.dirname(v); });
+  map[currentPackage] = '.';
+  return map;
+}
+
+/** Internal packages used by polymer. */
+// TODO(sigmund): consider computing this list by recursively parsing
+// pubspec.yaml files in the `Options.packageDirs`.
+final Set<String> _polymerPackageDependencies = (const [

[Jennifer Messerly, 2013/09/10 04:16:51]

fyi -- I don't think you need the parens.

also since this is lazy initialized anyway (the .toSet call) I don't think
"const" buys anything.

[Siggi Cherem (dart-lang), 2013/09/11 01:45:26]

good point. Done.

+    'analyzer_experimental', 'args', 'barback', 'browser', 'csslib',
+    'custom_element', 'fancy_syntax', 'html5lib', 'html_import', 'js',
+    'logging', 'mdv', 'meta', 'mutation_observer', 'observe', 'path', 'polymer',
+    'polymer_expressions', 'serialization', 'shadow_dom', 'source_maps',
+    'stack_trace', 'unittest', 'unmodifiable_collection', 'yaml']).toSet();
+
+/** Return the relative path of each file under [subDir] in [package]. */
+Iterable<String> _listPackageDir(String package, String subDir,
+    BarbackOptions options) {
+  var packageDir = options.packageDirs[package];
+  if (packageDir == null) return const [];
+  var dir = new Directory(path.join(packageDir, subDir));
+  if (!dir.existsSync()) return const [];
+  return dir.listSync(recursive: true, followLinks: false)
+      .where((f) => f is File)
+      .map((f) => path.relative(f.path, from: packageDir));
+}
+
+/** A simple provider that reads files directly from the pub cache. */
+class _PolymerPackageProvider implements PackageProvider {
+  Map<String, String> packageDirs;
+  Iterable<String> get packages => packageDirs.keys;
+
+  _PolymerPackageProvider(this.packageDirs);
+
+  Future<Asset> getAsset(AssetId id) => new Future.value(
+      new Asset.fromPath(id, path.join(packageDirs[id.package],
+      // Assets always use the posix style paths
+      path.joinAll(path.posix.split(id.path)))));
+}
+
+/** Tell barback which transformers to use and which assets to process. */
+void _initBarback(Barback barback, BarbackOptions options) {
+  var assets = [];
+  void addAssets(String package, String subDir) {
+    for (var filepath in _listPackageDir(package, subDir, options)) {
+      assets.add(new AssetId(package, filepath));
+    }
+  }
+
+  for (var package in options.packageDirs.keys) {
+    // There is nothing to do in the 'polymer' package and its dependencies.
+    if (!options.transformPolymerDependencies &&
+        _polymerPackageDependencies.contains(package)) continue;
+    barback.updateTransformers(package, options.phases);
+
+    // Notify barback to process anything under 'lib' and 'asset'.
+    addAssets(package, 'lib');
+    addAssets(package, 'asset');
+  }
+
+  // In case of the current package, include also 'web'.
+  addAssets(options.currentPackage, 'web');
+  if (options.transformTests) addAssets(options.currentPackage, 'test');
+
+  barback.updateSources(assets);
+}
+
+/** Attach error listeners on [barback] so we can report errors. */
+void _attachListeners(Barback barback) {
+  // Listen for errors and results
+  barback.errors.listen((e) {
+    var trace = getAttachedStackTrace(e);
+    if (trace != null) {
+      print(Trace.format(trace));
+    }
+    print('error running barback: $e');
+    exit(1);
+  });
+
+  barback.results.listen((result) {
+    if (!result.succeeded) {
+      print("build failed with errors: ${result.errors}");
+      exit(1);
+    }
+  });
+}
+
+/**
+ * Emits all outputs of [barback] and copies files that we didn't process (like
+ * polymer's libraries).
+ */
+Future _emitAllFiles(Barback barback, BarbackOptions options) {
+  return _emitFiles(barback, options, 'web').then((res) {
+    if (options.transformTests) return _emitFiles(barback, options, 'test');
+    return res;
+  });
+}
+
+Future _emitFiles(Barback barback, BarbackOptions options, String emitSubDir) {
+  return barback.getAllAssets().then((assets) {
+    // Copy all the assets we transformed
+    var futures = [];
+    for (var asset in assets) {
+      var id = asset.id;
+      var filepath;
+      if (id.package == options.currentPackage &&
+          id.path.startsWith('$emitSubDir/')) {
+        filepath = path.join(options.outDir, id.path);
+      } else if (id.path.startsWith('lib/')) {
+        filepath = path.join(options.outDir, emitSubDir, 'packages', id.package,
+            id.path.substring(4));
+      } else {
+        // TODO(sigmund): do something about other assets?
+        continue;
+      }
+
+      _ensureDir(path.dirname(filepath));
+      var writer = new File(filepath).openWrite();
+      futures.add(writer.addStream(asset.read()).then((_) => writer.close()));
+    }
+    return Future.wait(futures).then((_) {
+      // Copy also all the files we didn't process
+      var futures = [];
+      for (var package in _polymerPackageDependencies) {
+        for (var relpath in _listPackageDir(package, 'lib', options)) {
+          var inpath = path.join(options.packageDirs[package], relpath);
+          var outpath = path.join(options.outDir, emitSubDir,
+              'packages', package, relpath.substring(4));
+          _ensureDir(path.dirname(outpath));
+
+          var writer = new File(outpath).openWrite();
+          futures.add(writer.addStream(new File(inpath).openRead())
+            .then((_) => writer.close()));
+        }
+      }
+      return Future.wait(futures);
+    }).then((_) => assets);
+  });
+}
+
+/** Ensure [dirpath] exists. */
+void _ensureDir(var dirpath) {
+  new Directory(dirpath).createSync(recursive: true);
+}