Support user generated custom native JS classes.

pkg/compiler/lib/src/inferrer/node_tracer.dart

 // Copyright (c) 2013, 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 type_graph_inferrer;
 
 // A set of selectors we know do not escape the elements inside the
 // list.
 Set<String> doesNotEscapeListSet = new Set<String>.from(
   const <String>[
@@ skipping 168 matching lines @@
 
   void visitStringLiteralTypeInformation(StringLiteralTypeInformation info) {}
 
   void visitClosureTypeInformation(ClosureTypeInformation info) {}
 
   void visitClosureCallSiteTypeInformation(
       ClosureCallSiteTypeInformation info) {}
 
   visitStaticCallSiteTypeInformation(StaticCallSiteTypeInformation info) {
     Element called = info.calledElement;
+    if (called.isJsInterop) {
+      bailout('Used in JS Interop ${info.call}');

[sra1, 2015/10/01 20:55:27]

Seems harsh.
Describe what we want to happen here in a TODO.

I am worried that this is 'covering over' a lot of problems.

[Jacob, 2015/10/02 20:08:15]

Removed obsolete bailout hack.
This is a bailout I added when I was banging my head against why js interop type
inference was going wrong. Either this hack was never needed or I fixed
something along the way that made it obsolete. My tests till pass with minified
code without this check.

+    }
     if (inferrer.types.getInferredTypeOf(called) == currentUser) {
       addNewEscapeInformation(info);
     }
   }
 
   void analyzeStoredIntoList(ListTypeInformation list) {
     inferrer.analyzeListAndEnqueue(list);
     if (list.bailedOut) {
       bailout('Stored in a list that bailed out');
     } else {
@@ skipping 188 matching lines @@
     }
     if (isParameterOfListAddingMethod(info.element) ||
         isParameterOfMapAddingMethod(info.element)) {
       // These elements are being handled in
       // [visitDynamicCallSiteTypeInformation].
       return;
     }
     addNewEscapeInformation(info);
   }
 }