Encode super calls via extra properties on prototypes.

pkg/compiler/lib/src/js_backend/namer.dart

Index: pkg/compiler/lib/src/js_backend/namer.dart
diff --git a/pkg/compiler/lib/src/js_backend/namer.dart b/pkg/compiler/lib/src/js_backend/namer.dart
index 4eff34a459a1a27cfae6151df1b119eab7803b15..c4ab7b4361e01a4e838d249ee527e96abec772fd 100644
--- a/pkg/compiler/lib/src/js_backend/namer.dart
+++ b/pkg/compiler/lib/src/js_backend/namer.dart
@@ -220,6 +220,7 @@ class Namer implements ClosureNamer {
   final String currentIsolate = r'$';
   final String getterPrefix = r'get$';
   final String setterPrefix = r'set$';
+  final String superPrefix = r'super$';
   final String metadataField = '@';
   final String callPrefix = 'call';
   final String callCatchAllName = r'call$catchAll';
@@ -809,6 +810,15 @@ class Namer implements ClosureNamer {
   // TODO(ahe): Remove this method. Use get getNameOfMember instead.
   String getNameOfInstanceMember(Element member) => getNameX(member);
 
+  String getNameOfAliasedSuperMember(Element member) {
+    ClassElement superClass = member.enclosingClass;
+    String className = getNameOfClass(superClass);
+    String memberName = getNameOfMember(member);
+    String proposal = "$superPrefix$className\$$memberName";
+    // TODO(herhut): Use field naming constraints (unique wrt. inheritance).
+    return getMappedInstanceName(proposal);
+  }
+
   String getNameOfMember(Element member) => getNameX(member);
 
   String getNameOfGlobalField(VariableElement field) => getNameX(field);