Add a fallback mode for building summaries.

pkg/analyzer/lib/src/summary/summarize_elements.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 serialization.elements;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 120 matching lines @@
    */
   static const int currentMinorVersion = 0;
 
   final List<String> _linkedLibraryUris = <String>[];
   final List<LinkedLibraryBuilder> _linkedLibraries = <LinkedLibraryBuilder>[];
   final List<String> _unlinkedUnitUris = <String>[];
   final List<UnlinkedUnitBuilder> _unlinkedUnits = <UnlinkedUnitBuilder>[];
   final List<String> _unlinkedUnitHashes = <String>[];
 
   /**
+   * Add a fallback library to the package bundle, corresponding to the library
+   * whose defining compilation unit is located at [source].  Caller must also
+   * call [addFallbackUnit] for all compilation units contained in the library
+   * (including the defining compilation unit).
+   */
+  void addFallbackLibrary(Source source) {
+    String uri = source.uri.toString();
+    _linkedLibraryUris.add(uri);
+    _linkedLibraries.add(new LinkedLibraryBuilder(fallbackMode: true));
+  }
+
+  /**
+   * Add a fallback compilation unit to the package bundle, corresponding to
+   * the compilation unit located at [source].
+   */
+  void addFallbackUnit(Source source) {
+    String uri = source.uri.toString();
+    _unlinkedUnitUris.add(uri);
+    _unlinkedUnits
+        .add(new UnlinkedUnitBuilder(fallbackModePath: source.fullName));
+  }
+
+  /**
    * Assemble a new [PackageBundleBuilder] using the gathered information.
    */
   PackageBundleBuilder assemble() {
     return new PackageBundleBuilder(
         linkedLibraryUris: _linkedLibraryUris,
         linkedLibraries: _linkedLibraries,
         unlinkedUnitUris: _unlinkedUnitUris,
         unlinkedUnits: _unlinkedUnits,
         unlinkedUnitHashes: _unlinkedUnitHashes,
         majorVersion: currentMajorVersion,
@@ skipping 1429 matching lines @@
       exportNames.add(new LinkedExportNameBuilder(
           name: name,
           dependency: serializeDependency(dependentLibrary),
           unit: unit,
           kind: kind));
     }
     pb.exportNames = exportNames;
     return pb;
   }
 }