Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/polymer/src/build/polyfill_injector.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.
+
+/// Includes any additional polyfills that may needed by the deployed app.
+library polymer.src.build.polyfill_injector;
+
+import 'dart:async';
+
+import 'package:barback/barback.dart';
+import 'package:html5lib/dom.dart' show
+    Document, DocumentFragment, Element, Node;
+import 'package:html5lib/parser.dart' show parseFragment;
+import 'package:code_transformers/messages/build_logger.dart';
+import 'common.dart';
+
+/// Ensures that any scripts and polyfills needed to run a polymer application
+/// are included.
+///
+/// This step also replaces "packages/browser/dart.js" and the Dart script tag
+/// with a script tag that loads the dart2js compiled code directly.
+class PolyfillInjector extends Transformer with PolymerTransformer {
+  final TransformOptions options;
+
+  PolyfillInjector(this.options);
+
+  /// Only run on entry point .html files.
+  // TODO(nweiz): This should just take an AssetId when barback <0.13.0 support
+  // is dropped.
+  Future<bool> isPrimary(idOrAsset) {
+    var id = idOrAsset is AssetId ? idOrAsset : idOrAsset.id;
+    return new Future.value(options.isHtmlEntryPoint(id));
+  }
+
+  Future apply(Transform transform) {
+    var logger = new BuildLogger(transform,
+        convertErrorsToWarnings: !options.releaseMode,
+        detailsUri: 'http://goo.gl/5HPeuP');
+    return readPrimaryAsHtml(transform, logger).then((document) {
+      bool dartSupportFound = false;
+      Element webComponentsJs;
+      Element dartJs;
+      final dartScripts = <Element>[];
+
+      for (var tag in document.querySelectorAll('script')) {
+        var src = tag.attributes['src'];
+        if (src != null) {
+          var last = src.split('/').last;
+          if (_webComponentsJS.hasMatch(last)) {
+            webComponentsJs = tag;
+          } else if (_platformJS.hasMatch(last)) {
+            tag.attributes['src'] = src.replaceFirst(
+                _platformJS, 'webcomponents.min.js');
+            webComponentsJs = tag;
+          } else if (_dartSupportJS.hasMatch(last)) {
+            dartSupportFound = true;
+          } else if (last == 'dart.js') {
+            dartJs = tag;
+          }
+        }
+
+        if (tag.attributes['type'] == 'application/dart') {
+          dartScripts.add(tag);
+        }
+      }
+
+      if (dartScripts.isEmpty) {
+        // This HTML has no Dart code, there is nothing to do here.
+        transform.addOutput(transform.primaryInput);
+        return;
+      }
+
+      // Remove "packages/browser/dart.js". It is not needed in release mode,
+      // and in debug mode we want to ensure it is the last script on the page.
+      if (dartJs != null) dartJs.remove();
+
+      // TODO(jmesserly): ideally we would generate an HTML that loads
+      // dart2dart too. But for now dart2dart is not a supported deployment
+      // target, so just inline the JS script. This has the nice side effect of
+      // fixing our tests: even if content_shell supports Dart VM, we'll still
+      // test the compiled JS code.
+      if (options.directlyIncludeJS) {
+        // Replace all other Dart script tags with JavaScript versions.
+        for (var script in dartScripts) {
+          final src = script.attributes['src'];
+          if (src.endsWith('.dart')) {
+            script.attributes.remove('type');
+            script.attributes['src'] = '$src.js';
+            // TODO(sigmund): we shouldn't need 'async' here. Remove this
+            // workaround for dartbug.com/19653.
+            script.attributes['async'] = '';
+          }
+        }
+      } else {
+        document.body.nodes.add(parseFragment(
+              '<script src="packages/browser/dart.js"></script>'));
+      }
+
+      _addScriptFirst(urlSegment) {
+        document.head.nodes.insert(0, parseFragment(
+              '<script src="packages/$urlSegment"></script>\n'));
+      }
+
+      // Inserts dart_support.js either at the top of the document or directly
+      // after webcomponents.js if it exists.
+      if (!dartSupportFound) {
+        if (webComponentsJs == null) {
+          _addScriptFirst('web_components/dart_support.js');
+        } else {
+          var parentsNodes = webComponentsJs.parentNode.nodes;
+          parentsNodes.insert(
+              parentsNodes.indexOf(webComponentsJs) + 1,
+              parseFragment(
+                  '\n<script src="packages/web_components/dart_support.js">'
+                  '</script>'));
+        }
+      }
+
+      // By default webcomponents.js should come before all other scripts.
+      if (webComponentsJs == null && options.injectWebComponentsJs) {
+        var suffix = options.releaseMode ? '.min.js' : '.js';
+        _addScriptFirst('web_components/webcomponents$suffix');
+      }
+
+      transform.addOutput(
+          new Asset.fromString(transform.primaryInput.id, document.outerHtml));
+    });
+  }
+}
+
+final _platformJS = new RegExp(r'platform.*\.js', caseSensitive: false);
+final _webComponentsJS =
+    new RegExp(r'webcomponents.*\.js', caseSensitive: false);
+final _dartSupportJS = new RegExp(r'dart_support.js', caseSensitive: false);