Revert "cleanup unused incremental resolution"

pkg/front_end/lib/src/scanner/token.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.
 
 /**
  * Defines the tokens that are produced by the scanner, used by the parser, and
  * referenced from the [AST structure](ast.dart).
  */
 import 'dart:collection';
 
@@ skipping 67 matching lines @@
   @override
   CommentToken get precedingComments => _precedingComment;
 
   @override
   void set precedingComments(CommentToken comment) {
     _precedingComment = comment;
     _setCommentParent(_precedingComment);
   }
 
   @override
+  void applyDelta(int delta) {
+    super.applyDelta(delta);
+    Token token = precedingComments;
+    while (token != null) {
+      token.applyDelta(delta);
+      token = token.next;
+    }
+  }
+
+  @override
   Token copy() =>
       new BeginTokenWithComment(type, offset, copyComments(precedingComments));
 }
 
 /**
  * A token representing a comment.
  */
 class CommentToken extends StringToken {
   /**
    * The token that contains this comment.
@@ skipping 375 matching lines @@
 
   @override
   CommentToken get precedingComments => _precedingComment;
 
   void set precedingComments(CommentToken comment) {
     _precedingComment = comment;
     _setCommentParent(_precedingComment);
   }
 
   @override
+  void applyDelta(int delta) {
+    super.applyDelta(delta);
+    Token token = precedingComments;
+    while (token != null) {
+      token.applyDelta(delta);
+      token = token.next;
+    }
+  }
+
+  @override
   Token copy() => new KeywordTokenWithComment(
       keyword, offset, copyComments(precedingComments));
 }
 
 /**
  * A token that was scanned from the input. Each token knows which tokens
  * precede and follow it, acting as a link in a doubly linked list of tokens.
  */
 class SimpleToken implements Token {
   /**
@@ skipping 62 matching lines @@
   @override
   String get lexeme => type.lexeme;
 
   @override
   CommentToken get precedingComments => null;
 
   @override
   String get stringValue => type.stringValue;
 
   @override
+  void applyDelta(int delta) {
+    offset += delta;
+  }
+
+  @override
   Token copy() => new Token(type, offset);
 
   @override
   Token copyComments(Token token) {
     if (token == null) {
       return null;
     }
     Token head = token.copy();
     Token tail = head;
     token = token.next;
@@ skipping 97 matching lines @@
 
   @override
   CommentToken get precedingComments => _precedingComment;
 
   void set precedingComments(CommentToken comment) {
     _precedingComment = comment;
     _setCommentParent(_precedingComment);
   }
 
   @override
+  void applyDelta(int delta) {
+    super.applyDelta(delta);
+    Token token = precedingComments;
+    while (token != null) {
+      token.applyDelta(delta);
+      token = token.next;
+    }
+  }
+
+  @override
   Token copy() => new StringTokenWithComment(
       type, lexeme, offset, copyComments(precedingComments));
 }
 
 /**
  * A synthetic keyword token.
  */
 class SyntheticKeywordToken extends KeywordToken {
   /**
    * Initialize a newly created token to represent the given [keyword] at the
@@ skipping 162 matching lines @@
    * returns false because stringValue returns [:null:].
    */
   String get stringValue;
 
   /**
    * Return the type of the token.
    */
   TokenType get type;
 
   /**
+   * Apply (add) the given [delta] to this token's offset.
+   */
+  void applyDelta(int delta);
+
+  /**
    * Return a newly created token that is a copy of this tokens
    * including any [preceedingComment] tokens,
    * but that is not a part of any token stream.
    */
   Token copy();
 
   /**
    * Copy a linked list of comment tokens identical to the given comment tokens.
    */
   Token copyComments(Token token);
@@ skipping 744 matching lines @@
 
   void set precedingComments(CommentToken comment) {
     _precedingComment = comment;
     _setCommentParent(_precedingComment);
   }
 
   @override
   Token copy() =>
       new TokenWithComment(type, offset, copyComments(precedingComments));
 }