Make getKeys, getValues getters (keys, values).

lib/compiler/implementation/lib/constant_map.dart

Index: lib/compiler/implementation/lib/constant_map.dart
diff --git a/lib/compiler/implementation/lib/constant_map.dart b/lib/compiler/implementation/lib/constant_map.dart
index 3e340335be29b4d5651e95d4b7d3f47d94437518..fcbd58a95300842862e5c5707fc3ba8167fda9d3 100644
--- a/lib/compiler/implementation/lib/constant_map.dart
+++ b/lib/compiler/implementation/lib/constant_map.dart
@@ -11,7 +11,7 @@ class ConstantMap<V> implements Map<String, V> {
   final List<String> _keys;
 
   bool containsValue(V needle) {
-    return getValues().some((V value) => value == needle);
+    return values.some((V value) => value == needle);
   }
 
   bool containsKey(String key) {
@@ -28,9 +28,9 @@ class ConstantMap<V> implements Map<String, V> {
     _keys.forEach((String key) => f(key, this[key]));
   }
 
-  Collection<String> getKeys() => _keys;
+  Collection<String> get keys => _keys;
 
-  Collection<V> getValues() {
+  Collection<V> get values {
     List<V> result = <V>[];
     _keys.forEach((String key) => result.add(this[key]));
     return result;