Deserialize ResolvedAsts and ResolutionImpacts only when needed for compilation.

pkg/compiler/lib/src/serialization/task.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.
 
 library dart2js.serialization.task;
 
 import 'dart:async' show EventSink, Future;
 
 import '../common/resolution.dart' show ResolutionImpact, ResolutionWorkItem;
 import '../common/tasks.dart' show CompilerTask;
@@ skipping 23 matching lines @@
 
   DeserializerSystem deserializer;
 
   String get name => 'Serialization';
 
   /// If `true`, data must be retained to support serialization.
   // TODO(johnniwinther): Make this more precise in terms of what needs to be
   // retained, for instance impacts, resolution data etc.
   bool supportSerialization = false;
 
+  /// Set this flag to also deserialize [ResolvedAst]s and [ResolutionImpact]s
+  /// in `resolveOnly` mode. Use this for testing only.
+  bool deserializeCompilationDataForTesting = false;
+
   /// If `true`, deserialized data is supported.
   bool get supportsDeserialization => deserializer != null;
 
   /// Returns the [LibraryElement] for [resolvedUri] if available from
   /// serialization.
   Future<LibraryElement> readLibrary(Uri resolvedUri) {
     if (deserializer == null) return new Future<LibraryElement>.value();
     return deserializer.readLibrary(resolvedUri);
   }
 
@@ skipping 56 matching lines @@
       sink
         ..add(createSerializer(libraries)
             .toText(const JsonSerializationEncoder()))
         ..close();
     });
   }
 
   void deserializeFromText(Uri sourceUri, String serializedData) {
     measure(() {
       if (deserializer == null) {
-        deserializer = new DeserializerSystemImpl(compiler);
+        deserializer = new ResolutionDeserializerSystem(compiler,
+            deserializeCompilationDataForTesting:
+                deserializeCompilationDataForTesting);
       }
-      DeserializerSystemImpl deserializerImpl = deserializer;
+      ResolutionDeserializerSystem deserializerImpl = deserializer;
       DeserializationContext context = deserializerImpl.deserializationContext;
       Deserializer dataDeserializer = new Deserializer.fromText(
           context, sourceUri, serializedData, const JsonSerializationDecoder());
       context.deserializers.add(dataDeserializer);
     });
   }
 }
 
 /// A [ResolutionWorkItem] for a deserialized element.
 ///
@@ skipping 22 matching lines @@
 /// elements.
 abstract class DeserializerSystem {
   Future<LibraryElement> readLibrary(Uri resolvedUri);
   bool isDeserialized(Element element);
   bool hasResolvedAst(ExecutableElement element);
   ResolvedAst getResolvedAst(ExecutableElement element);
   bool hasResolutionImpact(Element element);
   ResolutionImpact getResolutionImpact(Element element);
   WorldImpact computeWorldImpact(Element element);
 }