Move registering of interceptors to the JsBackend.

lib/compiler/implementation/compiler.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.
 
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
 const bool REPORT_EXCESS_RESOLUTION = false;
@@ skipping 68 matching lines @@
   abstract List<CompilerTask> get tasks;
 
   // TODO(ahe,karlklose): rename this?
   void dumpInferredTypes() {}
 
   ItemCompilationContext createItemCompilationContext() {
     return new ItemCompilationContext();
   }
 
   SourceString getCheckedModeHelper(DartType type) => null;
+
+  abstract Element getInterceptor(Selector selector);
 }
 
 abstract class Compiler implements DiagnosticListener {
   final Map<String, LibraryElement> libraries;
   int nextFreeClassId = 0;
   World world;
   String assembledCode;
   Types types;
 
   final bool enableMinification;
@@ skipping 751 matching lines @@
  * information in the generated error message.
  */
 bool invariant(Spannable spannable, var condition, {String message: null}) {
   // TODO(johnniwinther): Use [spannable] and [message] to provide better
   // information on assertion errors.
   if (condition is Function){
     condition = condition();
   }
   return spannable != null && condition;
 }