merge PrecedenceInfo into TokenType and update all refs

pkg/front_end/test/fasta/parser/token_stream_rewriter_test.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 license that can be found in the LICENSE file.
 
 import 'package:front_end/src/fasta/parser/token_stream_rewriter.dart';
-import 'package:front_end/src/fasta/scanner/precedence.dart';
 import 'package:front_end/src/fasta/scanner/token.dart';
+import 'package:front_end/src/scanner/token.dart' show TokenType;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(TokenStreamRewriterTest_NoPrevious);
     defineReflectiveTests(TokenStreamRewriterTest_UsingPrevious);
   });
 }
 
@@ skipping 96 matching lines @@
     int eofOffset = head.charOffset + head.lexeme.length;
     if (eofOffset < 0) eofOffset = 0;
     Token eof = new SymbolToken.eof(eofOffset);
     if (!setPrevious) eof.previousToken = null;
     head.next = eof;
     if (setPrevious) eof.previousToken = head;
     return eof;
   }
 
   BeginGroupToken _makeBeginGroupToken(int charOffset) {
-    return new BeginGroupToken(OPEN_PAREN_INFO, charOffset);
+    return new BeginGroupToken(TokenType.OPEN_PAREN, charOffset);
   }
 
   StringToken _makeToken(int charOffset, String text) {
     return new StringToken.fromString(null, text, charOffset);
   }
 }
 
 /// Concrete implementation of [TokenStreamRewriterTest] in which
 /// [Token.previousToken] values are set to null.
 ///
 /// This forces [TokenStreamRewriter] to use its more complex heursitc for
 /// finding previous tokens.
 @reflectiveTest
 class TokenStreamRewriterTest_NoPrevious extends TokenStreamRewriterTest {
   bool get setPrevious => false;
 }
 
 /// Concrete implementation of [TokenStreamRewriterTest] in which
 /// [Token.previousToken] values are set to non-null.
 ///
 /// Since [TokenStreamRewriter] makes use of [Token.previousToken] when it can,
 /// these tests do not exercise the more complex heuristics for finding previous
 /// tokens.
 @reflectiveTest
 class TokenStreamRewriterTest_UsingPrevious extends TokenStreamRewriterTest {
   bool get setPrevious => true;
 }