Reapply 47ecf72 after it was reverted in e431e93e872d9a1c97a5177ebb09d5416f1d659a.

pkg/kernel/lib/binary/ast_from_binary.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.
 library kernel.ast_from_binary;
 
 import 'dart:convert';
 import 'dart:typed_data';
 
 import '../ast.dart';
 import '../transformations/flags.dart';
@@ skipping 507 matching lines @@
     bool shouldWriteData = node == null || _isReadingLibraryImplementation;
     if (node == null) {
       node = new Field(null, reference: reference);
     }
     int fileOffset = readOffset();
     int fileEndOffset = readOffset();
     int flags = readByte();
     readUInt(); // parent class binary offset.
     var name = readName();
     var fileUri = readUriReference();
+    var documentationComment = readStringOrNullIfEmpty();
     var annotations = readAnnotationList(node);
     debugPath.add(node.name?.name ?? 'field');
     var type = readDartType();
     var initializer = readExpressionOption();
     int transformerFlags = getAndResetTransformerFlags();
     debugPath.removeLast();
     if (shouldWriteData) {
       node.fileOffset = fileOffset;
       node.fileEndOffset = fileEndOffset;
       node.flags = flags;
       node.name = name;
       node.fileUri = fileUri;
+      node.documentationComment = documentationComment;
       node.annotations = annotations;
       node.type = type;
       node.initializer = initializer;
       node.initializer?.parent = node;
       node.transformerFlags = transformerFlags;
     }
     return node;
   }
 
   Constructor readConstructor() {
     int tag = readByte();
     assert(tag == Tag.Constructor);
     var canonicalName = readCanonicalNameReference();
     var reference = canonicalName.getReference();
     Constructor node = reference.node;
     bool shouldWriteData = node == null || _isReadingLibraryImplementation;
     if (node == null) {
       node = new Constructor(null, reference: reference);
     }
     var fileOffset = readOffset();
     var fileEndOffset = readOffset();
     var flags = readByte();
     readUInt(); // parent class binary offset.
     var name = readName();
+    var documentationComment = readStringOrNullIfEmpty();
     var annotations = readAnnotationList(node);
     debugPath.add(node.name?.name ?? 'constructor');
     var function = readFunctionNode();
     pushVariableDeclarations(function.positionalParameters);
     pushVariableDeclarations(function.namedParameters);
     if (shouldWriteData) {
       _fillTreeNodeList(node.initializers, readInitializer, node);
     } else {
       _skipNodeList(readInitializer);
     }
     variableStack.length = 0;
     var transformerFlags = getAndResetTransformerFlags();
     debugPath.removeLast();
     if (shouldWriteData) {
       node.fileOffset = fileOffset;
       node.fileEndOffset = fileEndOffset;
       node.flags = flags;
       node.name = name;
+      node.documentationComment = documentationComment;
       node.annotations = annotations;
       node.function = function..parent = node;
       node.transformerFlags = transformerFlags;
     }
     return node;
   }
 
   Procedure readProcedure() {
     int tag = readByte();
     assert(tag == Tag.Procedure);
     var canonicalName = readCanonicalNameReference();
     var reference = canonicalName.getReference();
     Procedure node = reference.node;
     bool shouldWriteData = node == null || _isReadingLibraryImplementation;
     if (node == null) {
       node = new Procedure(null, null, null, reference: reference);
     }
     var fileOffset = readOffset();
     var fileEndOffset = readOffset();
     int kindIndex = readByte();
     var kind = ProcedureKind.values[kindIndex];
     var flags = readByte();
     readUInt(); // parent class binary offset.
     var name = readName();
     var fileUri = readUriReference();
+    var documentationComment = readStringOrNullIfEmpty();
     var annotations = readAnnotationList(node);
     debugPath.add(node.name?.name ?? 'procedure');
     var function = readFunctionNodeOption();
     var transformerFlags = getAndResetTransformerFlags();
     debugPath.removeLast();
     if (shouldWriteData) {
       node.fileOffset = fileOffset;
       node.fileEndOffset = fileEndOffset;
       node.kind = kind;
       node.flags = flags;
       node.name = name;
       node.fileUri = fileUri;
+      node.documentationComment = documentationComment;
       node.annotations = annotations;
       node.function = function;
       node.function?.parent = node;
       node.transformerFlags = transformerFlags;
     }
     return node;
   }
 
   Initializer readInitializer() {
     int tag = readByte();
@@ skipping 619 matching lines @@
       ..fileOffset = offset
       ..fileEqualsOffset = fileEqualsOffset;
   }
 
   int readOffset() {
     // Offset is saved as unsigned,
     // but actually ranges from -1 and up (thus the -1)
     return readUInt() - 1;
   }
 }