more work aligning fasta.Token with analyzer.Token

pkg/front_end/lib/src/fasta/scanner/recover.dart

 // Copyright (c) 2017, 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 licenset hat can be found in the LICENSE file.
 
 library fasta.scanner.recover;
 
 import '../../scanner/token.dart' show TokenType;
 
 import '../fasta_codes.dart'
     show
@@ skipping 149 matching lines @@
     if (current is ErrorToken) {
       ErrorToken first = current;
       Token next = current;
       bool treatAsWhitespace = false;
       do {
         current = next;
         if (errorTail == null) {
           error = next;
         } else {
           errorTail.next = next;
-          next.previousToken = errorTail;
+          next.previous = errorTail;
         }
         errorTail = next;
         next = next.next;
       } while (next is ErrorToken && first.errorCode == next.errorCode);
 
       FastaCode code = first.errorCode;
       if (code == codeEncoding ||
           code == codeNonAsciiWhitespace ||
           code == codeAsciiControlCharacter) {
         treatAsWhitespace = true;
@@ skipping 20 matching lines @@
         assert(current.next != null);
       } else {
         treatAsWhitespace = true;
       }
       if (treatAsWhitespace) continue;
     }
     if (goodTail == null) {
       good = current;
     } else {
       goodTail.next = current;
-      current.previousToken = goodTail;
+      current.previous = goodTail;
     }
     beforeGoodTail = goodTail;
     goodTail = current;
   }
 
-  error.previousToken = new SymbolToken.eof(-1)..next = error;
+  error.previous = new SymbolToken.eof(-1)..next = error;
   Token tail;
   if (good != null) {
     errorTail.next = good;
-    good.previousToken = errorTail;
+    good.previous = errorTail;
     tail = goodTail;
   } else {
     tail = errorTail;
   }
-  if (!tail.isEof)
-    tail.next = new SymbolToken.eof(tail.end)..previousToken = tail;
+  if (!tail.isEof) tail.next = new SymbolToken.eof(tail.end)..previous = tail;
   return error;
 }
 
 Token synthesizeToken(int charOffset, String value, TokenType type) {
   return new StringToken.fromString(type, value, charOffset);
 }
 
 Token skipToEof(Token token) {
   while (!token.isEof) {
     token = token.next;
   }
   return token;
 }
 
 String closeBraceFor(String openBrace) {
   return const {
     '(': ')',
     '[': ']',
     '{': '}',
     '<': '>',
     r'${': '}',
   }[openBrace];
 }