Repeats and fixes the changes landed & reverted as CL 1789553003.

pkg/compiler/lib/src/apiimpl.dart

 // Copyright (c) 2012, 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 leg_apiimpl;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:package_config/packages.dart';
 import 'package:package_config/packages_file.dart' as pkgs;
 import 'package:package_config/src/packages_impl.dart' show
     MapPackages,
     NonFilePackagesDirectoryPackages;
 import 'package:package_config/src/util.dart' show
     checkValidPackageUri;
 
 import '../compiler_new.dart' as api;
-import 'commandline_options.dart';
 import 'common.dart';
 import 'common/tasks.dart' show
     GenericTask;
 import 'compiler.dart';
-import 'diagnostics/diagnostic_listener.dart' show
-    DiagnosticOptions;
 import 'diagnostics/messages.dart' show
     Message;
 import 'elements/elements.dart' as elements;
 import 'environment.dart';
 import 'io/source_file.dart';
+import 'options.dart' show
+    CompilerOptions;
 import 'platform_configuration.dart' as platform_configuration;
 import 'script.dart';
 
 
 /// Implements the [Compiler] using a [api.CompilerInput] for supplying the
 /// sources.
 class CompilerImpl extends Compiler {
   api.CompilerInput provider;
   api.CompilerDiagnostics handler;
   Packages packages;
   bool mockableLibraryUsed = false;
 
   /// A mapping of the dart: library-names to their location.
   ///
   /// Initialized in [setupSdk].
   Map<String, Uri> sdkLibraries;
 
   GenericTask userHandlerTask;
   GenericTask userProviderTask;
   GenericTask userPackagesDiscoveryTask;
 
   Uri get libraryRoot => options.platformConfigUri.resolve(".");
 
   CompilerImpl(this.provider, api.CompilerOutput outputProvider,
-      this.handler, api.CompilerOptions options)
+      this.handler, CompilerOptions options)
       : super(options: options, outputProvider: outputProvider,
           environment: new _Environment(options.environment)) {
     _Environment env = environment;
     env.compiler = this;
     tasks.addAll([
         userHandlerTask = new GenericTask('Diagnostic handler', this),
         userProviderTask = new GenericTask('Input provider', this),
         userPackagesDiscoveryTask =
             new GenericTask('Package discovery', this),
     ]);
@@ skipping 361 matching lines @@
   }
 }
 
 /// For every 'dart:' library, a corresponding environment variable is set
 /// to "true". The environment variable's name is the concatenation of
 /// this prefix and the name (without the 'dart:'.
 ///
 /// For example 'dart:html' has the environment variable 'dart.library.html' set
 /// to "true".
 const String _dartLibraryEnvironmentPrefix = 'dart.library.';