Move some of analyzer's code generation utilities into front_end.

pkg/analyzer/tool/task_dependency_graph/generate.dart

 // Copyright (c) 2015, 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.
 
 /**
  * This file contains code to output a description of tasks and their
  * dependencies in ".dot" format.  Prior to running, the user should run "pub
  * get" in the analyzer directory to ensure that a "packages" folder exists.
  *
  * TODO(paulberry):
  * - Add general.dart and html.dart for completeness.
  * - Use Graphviz's "record" feature to produce more compact output
  *   (http://www.graphviz.org/content/node-shapes#record)
  * - Produce a warning if a result descriptor is found which isn't the output
  *   of exactly one task.
  * - Convert this tool to use package_config to find the package map.
  */
 library analyzer.tool.task_dependency_graph.generate;
 
 import 'dart:io' hide File;
 import 'dart:io' as io;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
-import 'package:analyzer/src/codegen/tools.dart';
 import 'package:analyzer/src/context/builder.dart';
 import 'package:analyzer/src/dart/sdk/sdk.dart';
 import 'package:analyzer/src/generated/constant.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
+import 'package:front_end/src/codegen/tools.dart';
 import 'package:path/path.dart' as path;
 import 'package:path/path.dart';
 
 /**
  * Generate the target .dot file.
  */
 main() {
   String script = Platform.script.toFilePath(windows: Platform.isWindows);
   String pkgPath = normalize(join(dirname(script), '..', '..'));
   GeneratedContent.generateAll(pkgPath, <GeneratedContent>[target, htmlTarget]);
@@ skipping 327 matching lines @@
   @override
   visitIdentifier(Identifier node) {
     Element element = node.staticElement;
     if (element is PropertyAccessorElement &&
         element.isGetter &&
         element.returnType.isSubtypeOf(type)) {
       callback(element);
     }
   }
 }