Split parser/listener.dart, parser/class_element_listener.dart and tokens/token.dart into smaller l…

pkg/compiler/lib/src/tree/tree.dart

Index: pkg/compiler/lib/src/tree/tree.dart
diff --git a/pkg/compiler/lib/src/tree/tree.dart b/pkg/compiler/lib/src/tree/tree.dart
index 5c5bde57c94302ceeabc3a9573eab2557ee9bdea..d4331b5cc701c76bcb5f961827a58dcd274ab8d9 100644
--- a/pkg/compiler/lib/src/tree/tree.dart
+++ b/pkg/compiler/lib/src/tree/tree.dart
@@ -9,13 +9,15 @@ import 'dart:collection';
 import '../diagnostics/spannable.dart' show
     Spannable,
     SpannableAssertionFailure;
+import '../tokens/precedence_constants.dart' as Precedence show
+    FUNCTION_INFO;
 import '../tokens/token.dart' show
     BeginGroupToken,
-    FUNCTION_INFO,
+    Token;
+import '../tokens/token_constants.dart' as Tokens show
     IDENTIFIER_TOKEN,
     KEYWORD_TOKEN,
-    PLUS_TOKEN,
-    Token;
+    PLUS_TOKEN;
 import '../util/util.dart';
 import '../util/characters.dart';