Simplify the API for incremental_resolved_ast_generator.

pkg/front_end/lib/src/incremental_resolved_ast_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/file_system/file_system.dart';
 import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
@@ skipping 51 matching lines @@
       await init();
     }
     // The analysis driver doesn't currently support an asynchronous file API,
     // so we have to find all the files first to read their contents.
     // TODO(paulberry): this is an unnecessary source of duplicate work and
     // should be eliminated ASAP.
     var graph =
         await graphForProgram([_source], _options, fileReader: _fileReader);
     // TODO(paulberry): collect no-longer-referenced files from _fileState and
     // _fileRepository.
-    var libraries = <Uri, ResolvedLibrary>{};
+    var libraries = <Uri, Map<Uri, CompilationUnit>>{};
     if (!_schedulerStarted) {
       _scheduler.start();
       _schedulerStarted = true;
     }
     for (var libraryCycle in graph.topologicallySortedCycles) {
       for (var libraryUri in libraryCycle.libraries.keys) {
         var libraryNode = libraryCycle.libraries[libraryUri];
         for (var partUri in libraryNode.parts) {
           // TODO(paulberry): resolve the part URI.
           _fileReader(partUri, partUri);
         }
       }
       for (var libraryUri in libraryCycle.libraries.keys) {
         var libraryNode = libraryCycle.libraries[libraryUri];
         var result =
             await _driver.getResult(_fileRepository.pathForUri(libraryUri));
         // TODO(paulberry): handle errors.
-        var definingCompilationUnit = result.unit;
-        var partUnits = <Uri, CompilationUnit>{};
+        var units = {libraryUri: result.unit};
         for (var partUri in libraryNode.parts) {
           // Really we ought to have a driver API that lets us request a
           // specific part of a given library.  Otherwise we will run into
           // problems if a part is included in multiple libraries.
           // TODO(paulberry): address this.
           var partResult =
               await _driver.getResult(_fileRepository.pathForUri(partUri));
           // TODO(paulberry): handle errors.
-          partUnits[partUri] = partResult.unit;
+          units[partUri] = partResult.unit;
         }
-        libraries[libraryUri] =
-            new ResolvedLibrary(definingCompilationUnit, partUnits);
+        libraries[libraryUri] = units;
       }
     }
     _driver.addFile(_fileRepository.pathForUri(_source));
     // TODO(paulberry): stop the scheduler
     return new DeltaLibraries(libraries);
   }
 
   Future<Null> init() async {
     // TODO(paulberry): can we just use null?
     var performanceLog = new driver.PerformanceLog(new _NullStringSink());
@@ skipping 181 matching lines @@
 class _SourceProxy extends BasicSource {
   @override
   final String fullName;
 
   _SourceProxy(Uri uri, this.fullName) : super(uri);
 
   int get modificationStamp => 0;
 
   noSuchMethod(Invocation invocation) => unimplemented();
 }