Encode super calls via extra properties on prototypes.

sdk/lib/_internal/compiler/implementation/js_emitter/old_emitter/class_builder.dart

Index: sdk/lib/_internal/compiler/implementation/js_emitter/old_emitter/class_builder.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_emitter/old_emitter/class_builder.dart b/sdk/lib/_internal/compiler/implementation/js_emitter/old_emitter/class_builder.dart
index deb4fc44ba18ce9d2125fa356e1766b665ec58c4..68b6bf2d2f5a04f4e37cb1237599b64a899c9e1c 100644
--- a/sdk/lib/_internal/compiler/implementation/js_emitter/old_emitter/class_builder.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_emitter/old_emitter/class_builder.dart
@@ -10,6 +10,7 @@ part of dart2js.js_emitter;
 class ClassBuilder {
   final List<jsAst.Property> properties = <jsAst.Property>[];
   final List<String> fields = <String>[];
+  final List<String> aliasedSuperMethods = <String>[];

[sra1, 2014/11/03 18:30:56]

Maybe allocate on first use since most classes don't have a supercall entry

[herhut, 2014/11/04 12:52:49]

The field is now gone.

 
   String superName;
   String functionType;
@@ -34,6 +35,10 @@ class ClassBuilder {
     fields.add(field);
   }
 
+  void addAliasedSuperMethod(String method) {
+    aliasedSuperMethods.add(method);
+  }
+
   jsAst.ObjectInitializer toObjectInitializer() {
     StringBuffer buffer = new StringBuffer();
     if (superName != null) {
@@ -44,6 +49,12 @@ class ClassBuilder {
       buffer.write(';');
     }
     buffer.writeAll(fields, ',');
+
+    if (aliasedSuperMethods.isNotEmpty) {
+      buffer.write(';');
+      buffer.writeAll(aliasedSuperMethods, ',');

[sra1, 2014/11/03 18:30:56]

I commented elsewhere about a canoncial order.
Sorting here would work.
Sorting a copy would make writing a non-mutating operation

   buffer.writeAll(aliasedSuperMethods.toList()..sort(), ',');

[herhut, 2014/11/04 12:52:49]

Not required in the new encoding.

+    }
+
     var classData = js.string('$buffer');
     if (fieldMetadata != null) {
       // If we need to store fieldMetadata, classData is turned into an array,