Extract CallStructure from Selector.

pkg/compiler/lib/src/elements/names.dart

Index: pkg/compiler/lib/src/elements/names.dart
diff --git a/pkg/compiler/lib/src/elements/names.dart b/pkg/compiler/lib/src/elements/names.dart
index 56f3bf1cc9a07d2017598995c36d3e709f215da6..38e094595e6ad5a8b10186aca69310370a6cf591 100644
--- a/pkg/compiler/lib/src/elements/names.dart
+++ b/pkg/compiler/lib/src/elements/names.dart
@@ -46,6 +46,8 @@ abstract class Name {
   /// privacy into account.
   bool isSimilarTo(Name other);
   int get similarHashCode;
+  
+  LibraryElement get library;
 }
 
 class PublicName implements Name {
@@ -72,6 +74,8 @@ class PublicName implements Name {
   bool isSimilarTo(Name other) =>
       text == other.text && isSetter == other.isSetter;
   int get similarHashCode => text.hashCode + 11 * isSetter.hashCode;
+  
+  LibraryElement get library => null;
 
   String toString() => isSetter ? '$text=' : text;
 }