Revert "Remove 'Element.docRange'."

pkg/analyzer/test/src/summary/resynthesize_test.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 test.src.serialization.elements_test;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/constant/value.dart';
@@ skipping 678 matching lines @@
       expect(rRuntimeType, oImpl.runtimeType);
     }
     expect(resynthesized.kind, original.kind);
     expect(resynthesized.location, original.location, reason: desc);
     expect(resynthesized.name, original.name);
     expect(resynthesized.nameOffset, original.nameOffset, reason: desc);
     expect(rImpl.codeOffset, oImpl.codeOffset, reason: desc);
     expect(rImpl.codeLength, oImpl.codeLength, reason: desc);
     expect(resynthesized.documentationComment, original.documentationComment,
         reason: desc);
+    expect(resynthesized.docRange, original.docRange, reason: desc);
     compareMetadata(resynthesized.metadata, original.metadata, desc);
 
     // Validate modifiers.
     for (Modifier modifier in Modifier.values) {
       bool got = _hasModifier(resynthesized, modifier);
       bool want = _hasModifier(original, modifier);
       expect(got, want,
           reason: 'Mismatch in $desc.$modifier: got $got, want $want');
     }
 
@@ skipping 3957 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }