Use sdk summaries in front_end/kernel_generator.

pkg/front_end/lib/compiler_options.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.
 
 library front_end.compiler_options;
 
 import 'compilation_error.dart';
 import 'file_system.dart';
 import 'physical_file_system.dart';
 
@@ skipping 79 matching lines @@
   /// evaluation.
   Map<String, String> declaredVariables;
 
   /// The [FileSystem] which should be used by the front end to access files.
   ///
   /// All file system access performed by the front end goes through this
   /// mechanism, with one exception: if no value is specified for
   /// [packagesFilePath], the packages file is located using the actual physical
   /// file system.  TODO(paulberry): fix this.
   FileSystem fileSystem = PhysicalFileSystem.instance;
+
+  /// Whether to generate code for the SDK when compiling a whole-program.
+  bool compileSdk = false;
+
+  /// Whether a modular build compiles only the files listed explicitly or if it
+  /// compiles dependencies as well.
+  ///
+  /// This option is intended only for modular APIs like `kernelForBuildUnit`.
+  /// These APIs by default ensure that builds are hermetic, where all files
+  /// that will be compiled are listed explicitly and all other dependencies
+  /// are covered by summary files.
+  ///
+  /// When this option is true, these APIs will treat any dependency that is
+  /// not described in a summary as if it was explictly listed as an input.
+  bool chaseDependencies = false;
+
+  /// Whether to intepret Dart sources in strong-mode.
+  bool strongMode = true;
 }