Encode super calls via extra properties on prototypes.

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js_backend;
 
 const VERBOSE_OPTIMIZER_HINTS = false;
 
 class JavaScriptItemCompilationContext extends ItemCompilationContext {
   final Set<HInstruction> boundsChecked = new Set<HInstruction>();
@@ skipping 305 matching lines @@
    * (unintercepted) classes.
    */
   final Set<ClassElement> classesMixedIntoInterceptedClasses =
       new Set<ClassElement>();
 
   /**
    * Set of classes whose `operator ==` methods handle `null` themselves.
    */
   final Set<ClassElement> specialOperatorEqClasses = new Set<ClassElement>();
 
+  /**
+   * A Map from classes to the members of superclasses they call via super.
+   */
+  final Map<ClassElement, Set<Element>> aliasedSuperMembers =
+      new Map<ClassElement, Set<Element>>();
+
   List<CompilerTask> get tasks {
     return <CompilerTask>[builder, optimizer, generator, emitter];
   }
 
   final RuntimeTypes rti;
 
   /// Holds the method "disableTreeShaking" in js_mirrors when
   /// dart:mirrors has been loaded.
   FunctionElement disableTreeShakingMarker;
 
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   String registerOneShotInterceptor(Selector selector) {
     Set<ClassElement> classes = getInterceptedClassesOn(selector.name);
     String name = namer.getOneShotInterceptorName(selector, classes);
     if (!oneShotInterceptors.containsKey(name)) {
       registerSpecializedGetInterceptor(classes);
       oneShotInterceptors[name] = selector;
     }
     return name;
   }
 
+  void registerAliasedSuperMember(Element method, ClassElement caller) {
+    Set<Element> methods =
+        aliasedSuperMembers.putIfAbsent(caller, () => new Setlet<Element>());
+    methods.add(method);
+  }
+
+  Set<Element> getAliasedSuperMembers(ClassElement subclass) {
+    Set<Element> aliases = aliasedSuperMembers[subclass];
+    if (aliases == null) return const ImmutableEmptySet<Element>();
+    return aliases;
+  }
+
   bool isInterceptedMethod(Element element) {
     if (!element.isInstanceMember) return false;
     if (element.isGenerativeConstructorBody) {
       return Elements.isNativeOrExtendsNative(element.enclosingClass);
     }
     return interceptedElements[element.name] != null;
   }
 
   bool fieldHasInterceptedGetter(Element element) {
     assert(element.isField);
@@ skipping 1900 matching lines @@
   }
 }
 
 /// Records that [constant] is used by the element behind [registry].
 class Dependency {
   final ConstantValue constant;
   final Element annotatedElement;
 
   const Dependency(this.constant, this.annotatedElement);
 }