Use configurations and declared variables to select import/export URIs during prelinking.

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

Index: pkg/analyzer/lib/src/summary/pub_summary.dart
diff --git a/pkg/analyzer/lib/src/summary/pub_summary.dart b/pkg/analyzer/lib/src/summary/pub_summary.dart
index e84431294162c35ab30f91f292cf596223de3e4b..589118361ebeaf0a3c81b3eae9d4183ad6ace9e4 100644
--- a/pkg/analyzer/lib/src/summary/pub_summary.dart
+++ b/pkg/analyzer/lib/src/summary/pub_summary.dart
@@ -741,6 +741,9 @@ class _LinkedWalker extends DependencyWalker<_LinkedNode> {
       return store.linkedMap[uri];
     }, (String uri) {
       return store.unlinkedMap[uri];
+    }, (String name) {
+      // TODO(scheglov) decide how to use declared variables in Pub
+      return null;
     }, strong);
     // Assemble linked bundles and put them into the store.
     for (_LinkedNode node in scc) {