Convert GeneratedContent to async and use AnalysisDriver for tasks graph.

pkg/analyzer/tool/summary/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 generate serialization/deserialization logic for
  * summaries based on an "IDL" description of the summary format (written in
  * stylized Dart).
  *
  * For each class in the "IDL" input, two corresponding classes are generated:
@@ skipping 12 matching lines @@
 import 'dart:io';
 
 import 'package:front_end/src/codegen/tools.dart';
 import 'package:front_end/src/fasta/scanner/string_scanner.dart';
 import 'package:front_end/src/scanner/token.dart' show Token;
 import 'package:path/path.dart';
 
 import 'idl_model.dart' as idlModel;
 import 'mini_ast.dart';
 
-main() {
+main() async {
   String script = Platform.script.toFilePath(windows: Platform.isWindows);
   String pkgPath = normalize(join(dirname(script), '..', '..'));
-  GeneratedContent.generateAll(pkgPath, allTargets);
+  await GeneratedContent.generateAll(pkgPath, allTargets);
 }
 
 final List<GeneratedContent> allTargets = <GeneratedContent>[
   formatTarget,
   schemaTarget
 ];
 
 final GeneratedFile formatTarget =
-    new GeneratedFile('lib/src/summary/format.dart', (String pkgPath) {
+    new GeneratedFile('lib/src/summary/format.dart', (String pkgPath) async {
   _CodeGenerator codeGenerator = new _CodeGenerator(pkgPath);
   codeGenerator.generateFormatCode();
   return codeGenerator._outBuffer.toString();
 });
 
 final GeneratedFile schemaTarget =
-    new GeneratedFile('lib/src/summary/format.fbs', (String pkgPath) {
+    new GeneratedFile('lib/src/summary/format.fbs', (String pkgPath) async {
   _CodeGenerator codeGenerator = new _CodeGenerator(pkgPath);
   codeGenerator.generateFlatBufferSchema();
   return codeGenerator._outBuffer.toString();
 });
 
 typedef String _StringToString(String s);
 
 class _CodeGenerator {
   static const String _throwDeprecated =
       "throw new UnimplementedError('attempt to access deprecated field')";
@@ skipping 944 matching lines @@
       Token token = comment.tokens.first;
       return token.lexeme.split('\n').map((String line) {
         line = line.trimLeft();
         if (line.startsWith('*')) line = ' ' + line;
         return line;
       }).join('\n');
     }
     return null;
   }
 }