Use identical in token operators.

pkg/compiler/lib/src/serialization/serialization.dart

Index: pkg/compiler/lib/src/serialization/serialization.dart
diff --git a/pkg/compiler/lib/src/serialization/serialization.dart b/pkg/compiler/lib/src/serialization/serialization.dart
index 9bbfb8ddd91b217e30a4e35b18c47ebb1360b058..bdbc238a5f618f951deccf1736ec271472f38e30 100644
--- a/pkg/compiler/lib/src/serialization/serialization.dart
+++ b/pkg/compiler/lib/src/serialization/serialization.dart
@@ -4,6 +4,9 @@
 
 library dart2js.serialization;
 
+import 'package:front_end/src/fasta/scanner/precedence.dart' show
+    PrecedenceInfo;
+
 import '../common.dart';
 import '../common/resolution.dart';
 import '../constants/expressions.dart';
@@ -20,6 +23,16 @@ import 'values.dart';
 
 export 'task.dart' show LibraryDeserializer;
 
+final Map<String, String> canonicalNames = computeCanonicalNames();
+
+Map<String, String> computeCanonicalNames() {
+  Map<String, String> result = <String, String>{};
+  for (PrecedenceInfo info in PrecedenceInfo.all) {
+    result[info.value] = info.value;
+  }
+  return result;
+}
+
 /// An object that supports the encoding an [ObjectValue] for serialization.
 ///
 /// The [ObjectEncoder] ensures that nominality and circularities of
@@ -471,7 +484,7 @@ abstract class AbstractDecoder<K> {
       }
       throw new StateError("String value '$key' not found in $_map.");
     }
-    return value;
+    return canonicalNames[value] ?? value;
   }
 
   /// Returns the list of [String] values associated with [key] in the decoded