Adding Angular and dependent packages for testing

third_party/pkg/angular/lib/tools/expression_extractor.dart

+library angular.tools.html_expression_extractor;
+
+import 'dart:io';
+import 'package:angular/tools/html_extractor.dart';
+import 'package:angular/tools/source_metadata_extractor.dart';
+import 'package:angular/tools/source_crawler_impl.dart';
+import 'package:angular/tools/io.dart';
+import 'package:angular/tools/io_impl.dart';
+import 'package:angular/tools/common.dart';
+
+import 'package:di/di.dart';
+import 'package:di/dynamic_injector.dart';
+import 'package:angular/core/parser/parser_library.dart';
+import 'package:angular/tools/parser_generator/dart_code_gen.dart';
+import 'package:angular/tools/parser_generator/generator.dart';
+
+main(args) {
+  if (args.length < 5) {
+    print('Usage: expression_extractor file_to_scan html_root header_file '
+          'footer_file output [package_roots+]');
+    exit(0);
+  }
+  IoService ioService = new IoServiceImpl();
+
+  var packageRoots =
+      (args.length < 6) ? [Platform.packageRoot] : args.sublist(5);
+  var sourceCrawler = new SourceCrawlerImpl(packageRoots);
+  var sourceMetadataExtractor = new SourceMetadataExtractor(sourceCrawler);
+  List<DirectiveInfo> directives =
+      sourceMetadataExtractor.gatherDirectiveInfo(args[0]);
+  var htmlExtractor = new HtmlExpressionExtractor(directives, ioService);
+  htmlExtractor.crawl(args[1]);
+
+  var expressions = htmlExtractor.expressions;
+  expressions.add('null');
+
+  var headerFile = args[2];
+  var footerFile = args[3];
+  var outputFile = args[4];
+  SourcePrinter _prt;
+  if (outputFile == '--') {
+    _prt = new SourcePrinter();
+  } else {
+    _prt = new FileSourcePrinter(outputFile);
+  }
+
+  // Output the header file first.
+  if (headerFile != '') {
+    _prt.printSrc(_readFile(headerFile));
+  }
+
+  _prt.printSrc('// Found ${expressions.length} expressions');
+  Module module = new Module()
+    ..type(ParserBackend, implementedBy: DartCodeGen)
+    ..value(SourcePrinter, _prt);
+  Injector injector =
+      new DynamicInjector(modules: [module], allowImplicitInjection: true);
+
+  // Run the generator.
+  injector.get(ParserGenerator).generateParser(htmlExtractor.expressions);
+
+  // Output footer last.
+  if (footerFile != '') {
+    _prt.printSrc(_readFile(footerFile));
+  }
+}
+
+String _readFile(String filePath) => new File(filePath).readAsStringSync();
+
+class FileSourcePrinter implements SourcePrinter {
+  final File _file;
+
+  FileSourcePrinter(String filePath)
+      : _file = new File(filePath) {
+    // clear file
+    _file.writeAsStringSync('');
+  }
+
+  printSrc(src) => _file.writeAsStringSync('$src\n', mode: FileMode.APPEND);
+}