Move the handling of operator[] into the new interceptors.

sdk/lib/_internal/compiler/implementation/ssa/tracer.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.
 
 library tracer;
 
 import 'dart:io';
 import 'ssa.dart';
 import '../js_backend/js_backend.dart';
 import '../dart2jslib.dart';
@@ skipping 288 matching lines @@
   String visitGenericInvoke(String invokeType, String functionName,
                             List<HInstruction> arguments) {
     StringBuffer argumentsString = new StringBuffer();
     for (int i = 0; i < arguments.length; i++) {
       if (i != 0) argumentsString.add(", ");
       argumentsString.add(temporaryId(arguments[i]));
     }
     return "$invokeType: $functionName($argumentsString)";
   }
 
-  String visitIndex(HIndex node) => visitInvokeStatic(node);
+  String visitIndex(HIndex node) {
+    String receiver = temporaryId(node.receiver);
+    String index = temporaryId(node.index);
+    return "Index: $receiver[$index]";
+  }
+
   String visitIndexAssign(HIndexAssign node) => visitInvokeStatic(node);
 
   String visitIntegerCheck(HIntegerCheck node) {
     String value = temporaryId(node.value);
     return "Integer check: $value";
   }
 
   String visitInterceptor(HInterceptor node) {
     String value = temporaryId(node.inputs[0]);
     return "Intercept: $value";
@@ skipping 210 matching lines @@
   }
 
   String visitTypeConversion(HTypeConversion node) {
     return "TypeConversion: ${temporaryId(node.checkedInput)} to ${node.type}";
   }
 
   String visitRangeConversion(HRangeConversion node) {
     return "RangeConversion: ${node.checkedInput}";
   }
 }