Start unraveling circularities between analyzer and front_end/kernel.

pkg/front_end/lib/src/incremental_kernel_generator_impl.dart

 // Copyright (c) 2017, 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 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:front_end/incremental_kernel_generator.dart';
 import 'package:front_end/incremental_resolved_ast_generator.dart';
 import 'package:front_end/src/base/processed_options.dart';
 import 'package:front_end/src/base/source.dart';
 import 'package:front_end/src/incremental_resolved_ast_generator_impl.dart';
-import 'package:kernel/analyzer/loader.dart';
+import 'package:analyzer/src/kernel/loader.dart';
 import 'package:kernel/kernel.dart' hide Source;
 
 dynamic unimplemented() {
   // TODO(paulberry): get rid of this.
   throw new UnimplementedError();
 }
 
 DartOptions _convertOptions(ProcessedOptions options) {
   // TODO(paulberry): make sure options.compileSdk is handled correctly.
   return new DartOptions(
@@ skipping 108 matching lines @@
   Source forUri2(Uri absoluteUri) => new _SourceProxy(absoluteUri);
 
   noSuchMethod(Invocation invocation) => unimplemented();
 }
 
 class _SourceProxy extends BasicSource {
   _SourceProxy(Uri uri) : super(uri);
 
   noSuchMethod(Invocation invocation) => unimplemented();
 }