Use List<String> for combinators in summaries.

pkg/analyzer/lib/src/summary/resynthesize.dart

Index: pkg/analyzer/lib/src/summary/resynthesize.dart
diff --git a/pkg/analyzer/lib/src/summary/resynthesize.dart b/pkg/analyzer/lib/src/summary/resynthesize.dart
index 7adfa645baf7617601a27a864ad4b522532681c6..403467974caebe4cf0fe6c873fd2abb2c18a3f23 100644
--- a/pkg/analyzer/lib/src/summary/resynthesize.dart
+++ b/pkg/analyzer/lib/src/summary/resynthesize.dart
@@ -349,13 +349,11 @@ class _LibraryResynthesizer {
     if (serializedCombinator.shows.isNotEmpty) {
       ShowElementCombinatorImpl combinator = new ShowElementCombinatorImpl();
       combinator.shownNames = serializedCombinator.shows
-          .map((UnlinkedCombinatorName n) => n.name)
           .toList();

[scheglov, 2016/01/04 17:21:50]

AFAIK it is List already.

[Paul Berry, 2016/01/04 18:07:51]

Right, it is.  But I want to make a copy of the list because once we move to a
binary serialization format I believe it will be a class which implements List
and holds a reference to more data than just the list.  I've added a clarifying
comment.

       return combinator;
     } else {
       HideElementCombinatorImpl combinator = new HideElementCombinatorImpl();
       combinator.hiddenNames = serializedCombinator.hides
-          .map((UnlinkedCombinatorName n) => n.name)
           .toList();
       return combinator;
     }