Use unitMember/classMember/parameter names instead of offsets in index.

pkg/analyzer/test/src/summary/index_unit_test.dart

 // Copyright (c) 2016, 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:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
@@ skipping 1116 matching lines @@
     String packageIndexJsonString =
         new JsonEncoder.withIndent('  ').convert(packageIndex.toJson());
     fail('$msg in\n' + packageIndexJsonString);
   }
 
   /**
    * Return the [element] identifier in [packageIndex] or fail.
    */
   int _findElementId(Element element) {
     int unitId = _getUnitId(element);
-    ElementInfo info = PackageIndexAssembler.newElementInfo(unitId, element);
+    // Prepare the element that was put into the index.
+    IndexElementInfo info = new IndexElementInfo(element);
+    element = info.element;
+    // Prepare element's name components.
+    int unitMemberId = _getStringId(PackageIndexAssembler.NULL_STRING);
+    int classMemberId = _getStringId(PackageIndexAssembler.NULL_STRING);
+    int parameterId = _getStringId(PackageIndexAssembler.NULL_STRING);
+    for (Element e = element; e != null; e = e.enclosingElement) {
+      if (e.enclosingElement is CompilationUnitElement) {
+        unitMemberId = _getStringId(e.name);
+      }
+    }
+    for (Element e = element; e != null; e = e.enclosingElement) {
+      if (e.enclosingElement is ClassElement) {
+        classMemberId = _getStringId(e.name);
+      }
+    }
+    if (element is ParameterElement) {
+      parameterId = _getStringId(element.name);
+    }
+    // Find the element's id.
     for (int elementId = 0;
         elementId < packageIndex.elementUnits.length;
         elementId++) {
       if (packageIndex.elementUnits[elementId] == unitId &&
-          packageIndex.elementOffsets[elementId] == info.offset &&
+          packageIndex.elementNameUnitMemberIds[elementId] == unitMemberId &&
+          packageIndex.elementNameClassMemberIds[elementId] == classMemberId &&
+          packageIndex.elementNameParameterIds[elementId] == parameterId &&
           packageIndex.elementKinds[elementId] == info.kind) {
         return elementId;
       }
     }
     _failWithIndexDump('Element $element is not referenced');
     return 0;
   }
 
   /**
    * Return all relations with [element] in [unitIndex].
@@ skipping 156 matching lines @@
   final bool isQualified;
 
   _Relation(this.kind, this.offset, this.length, this.isQualified);
 
   @override
   String toString() {
     return '_Relation{kind: $kind, offset: $offset, length: $length, '
         'isQualified: $isQualified}';
   }
 }