Reapply 47ecf72 after it was reverted in e431e93e872d9a1c97a5177ebb09d5416f1d659a.

pkg/kernel/lib/binary/ast_to_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_to_binary;
 
 import '../ast.dart';
 import '../import_table.dart';
 import 'tag.dart';
 import 'dart:convert';
 import 'dart:typed_data';
@@ skipping 397 matching lines @@
     _variableIndexer = new VariableIndexer();
     writeByte(Tag.Constructor);
     writeCanonicalNameReference(getCanonicalNameOfMember(node));
     writeOffset(node.fileOffset);
     writeOffset(node.fileEndOffset);
     writeByte(node.flags);
     assert(node.parent is Class);
     Class parent = node.parent;
     writeUInt30(parent.binaryOffset);
     writeName(node.name ?? _emptyName);
+    writeStringReference(node.documentationComment ?? '');
     writeAnnotationList(node.annotations);
     assert(node.function.typeParameters.isEmpty);
     writeNode(node.function);
     // Parameters are in scope in the initializers.
     _variableIndexer.restoreScope(node.function.positionalParameters.length +
         node.function.namedParameters.length);
     writeNodeList(node.initializers);
     _variableIndexer = null;
   }
 
   visitProcedure(Procedure node) {
     if (node.canonicalName == null) {
       throw 'Missing canonical name for $node';
     }
     _variableIndexer = new VariableIndexer();
     writeByte(Tag.Procedure);
     writeCanonicalNameReference(getCanonicalNameOfMember(node));
     writeOffset(node.fileOffset);
     writeOffset(node.fileEndOffset);
     writeByte(node.kind.index);
     writeByte(node.flags);
     if (node.parent is Class) {
       Class parent = node.parent;
       writeUInt30(parent.binaryOffset);
     } else {
       writeUInt30(0); // 0 is a valid offset, but not for a class.
     }
     writeName(node.name ?? '');
     writeUriReference(node.fileUri ?? '');
+    writeStringReference(node.documentationComment ?? '');
     writeAnnotationList(node.annotations);
     writeOptionalNode(node.function);
     _variableIndexer = null;
   }
 
   visitField(Field node) {
     if (node.canonicalName == null) {
       throw 'Missing canonical name for $node';
     }
     _variableIndexer = new VariableIndexer();
     writeByte(Tag.Field);
     writeCanonicalNameReference(getCanonicalNameOfMember(node));
     writeOffset(node.fileOffset);
     writeOffset(node.fileEndOffset);
     writeByte(node.flags);
     if (node.parent is Class) {
       Class parent = node.parent;
       writeUInt30(parent.binaryOffset);
     } else {
       writeUInt30(0); // 0 is a valid offset, but not for a class.
     }
     writeName(node.name);
     writeUriReference(node.fileUri ?? '');
+    writeStringReference(node.documentationComment ?? '');
     writeAnnotationList(node.annotations);
     writeNode(node.type);
     writeOptionalNode(node.initializer);
     _variableIndexer = null;
   }
 
   visitInvalidInitializer(InvalidInitializer node) {
     writeByte(Tag.InvalidInitializer);
     writeByte(node.isSynthetic ? 1 : 0);
   }
@@ skipping 883 matching lines @@
     put(node.name);
     node.visitChildren(this);
   }
 
   visitClass(Class node) {
     putOptional(node.documentationComment);
     putOptional(node.name);
     node.visitChildren(this);
   }
 
+  @override
+  visitConstructor(Constructor node) {
+    putOptional(node.documentationComment);
+    super.visitConstructor(node);
+  }
+
+  @override
+  visitField(Field node) {
+    putOptional(node.documentationComment);
+    super.visitField(node);
+  }
+
   visitNamedExpression(NamedExpression node) {
     put(node.name);
     node.visitChildren(this);
   }
 
+  @override
+  visitProcedure(Procedure node) {
+    putOptional(node.documentationComment);
+    super.visitProcedure(node);
+  }
+
   visitStringLiteral(StringLiteral node) {
     put(node.value);
   }
 
   visitIntLiteral(IntLiteral node) {
     if (node.value.abs() >> 30 != 0) {
       put('${node.value}');
     }
   }
 
@@ skipping 127 matching lines @@
     _sink.add(_buffer.sublist(0, length));
     _buffer = new Uint8List(SIZE);
     flushedLength += length;
     length = 0;
   }
 
   void flushAndDestroy() {
     _sink.add(_buffer.sublist(0, length));
   }
 }