VM: [Kernel] Add --embedder-entry-points-manifest to dartk/transform and pass it to the treeshaker

pkg/kernel/bin/dartk.dart

 #!/usr/bin/env dart
 // Copyright (c) 2016, 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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'batch_util.dart';
+import 'util.dart';
 
 import 'package:args/args.dart';
 import 'package:kernel/analyzer/loader.dart';
 import 'package:kernel/application_root.dart';
 import 'package:kernel/verifier.dart';
 import 'package:kernel/kernel.dart';
 import 'package:kernel/log.dart';
 import 'package:kernel/target/targets.dart';
 import 'package:path/path.dart' as path;
 
@@ skipping 29 matching lines @@
       defaultsTo: 'vm')
   ..addFlag('strong',
       help: 'Load .dart files in strong mode.\n'
           'Does not affect loading of binary files. Strong mode support is very\n'
           'unstable and not well integrated yet.')
   ..addFlag('link', abbr: 'l', help: 'Link the whole program into one file.')
   ..addFlag('no-output', negatable: false, help: 'Do not output any files.')
   ..addOption('url-mapping',
       allowMultiple: true,
       help: 'A custom url mapping of the form `<scheme>:<name>::<uri>`.')
+  ..addOption('embedder-entry-points-manifest',
+      allowMultiple: true,
+      help: 'A path to a file describing entrypoints '
+          '(lines of the form `<library>,<class>,<member>`).')
   ..addFlag('verbose',
       abbr: 'v',
       negatable: false,
       help: 'Print internal warnings and diagnostics to stderr.')
   ..addFlag('print-metrics',
       negatable: false, help: 'Print performance metrics.')
   ..addOption('write-dependencies',
       help: 'Write all the .dart that were loaded to the given file.')
   ..addFlag('verify-ir', help: 'Perform slow internal correctness checks.')
   ..addFlag('tolerant',
@@ skipping 204 matching lines @@
   String file = options.rest.single;
   checkIsFile(file, option: 'Input file');
   file = new File(file).absolute.path;
   Uri fileUri = new Uri(scheme: 'file', path: file);
 
   String format = options['format'] ?? defaultFormat();
   String outputFile = options['out'] ?? defaultOutput();
 
   List<String> urlMapping = options['url-mapping'] as List<String>;
   var customUriMappings = parseCustomUriMappings(urlMapping);
+
+  List<String> embedderEntryPointManifests =
+      options['embedder-entry-points-manifest'] as List<String>;
+  List<ProgramRoot> programRoots =
+      parseProgramRoots(embedderEntryPointManifests);
+
   var repository = new Repository();
 
   Program program;
 
   var watch = new Stopwatch()..start();
   List<String> loadedFiles;
   Function getLoadedFiles;
   List errors = const [];
-  TargetFlags targetFlags = new TargetFlags(strongMode: options['strong']);
+  TargetFlags targetFlags = new TargetFlags(
+      strongMode: options['strong'], programRoots: programRoots);
   Target target = getTarget(options['target'], targetFlags);
 
   var declaredVariables = <String, String>{};
   declaredVariables.addAll(target.extraDeclaredVariables);
   for (String define in options['D']) {
     int separator = define.indexOf('=');
     if (separator == -1) {
       fail('Invalid define: -D$define. Format is -D<name>=<value>');
     }
     String name = define.substring(0, separator);
@@ skipping 93 matching lines @@
 
   await ioFuture;
 
   if (shouldReportMetrics) {
     int flushTime = watch.elapsedMilliseconds - time;
     print('writer.flush_time = $flushTime ms');
   }
 
   return errors.length > 0 ? CompilerOutcome.Fail : CompilerOutcome.Ok;
 }