Re-apply: Implement tracing for function expressions and statements, and infer types of parameters …

sdk/lib/_internal/lib/interceptors.dart

Index: sdk/lib/_internal/lib/interceptors.dart
===================================================================
--- sdk/lib/_internal/lib/interceptors.dart	(revision 31185)
+++ sdk/lib/_internal/lib/interceptors.dart	(working copy)
@@ -180,8 +180,7 @@
 var mapTypeToInterceptor;
 
 int findIndexForNativeSubclassType(Type type) {
-  JS_EFFECT((_){ mapTypeToInterceptor = _; });
-  if (mapTypeToInterceptor == null) return null;
+  if (JS('bool', '# == null', mapTypeToInterceptor)) return null;
   List map = JS('JSFixedArray', '#', mapTypeToInterceptor);
   for (int i = 0; i + 1 < map.length; i += 3) {
     if (type == map[i]) {
@@ -195,7 +194,7 @@
   var index = findIndexForNativeSubclassType(type);
   if (index == null) return null;
   List map = JS('JSFixedArray', '#', mapTypeToInterceptor);
-  return mapTypeToInterceptor[index + 1];
+  return map[index + 1];
 }
 
 /**
@@ -208,7 +207,7 @@
   var index = findIndexForNativeSubclassType(type);
   if (index == null) return null;
   List map = JS('JSFixedArray', '#', mapTypeToInterceptor);
-  var constructorMap = mapTypeToInterceptor[index + 2];
+  var constructorMap = map[index + 2];
   var constructorFn = JS('', '#[#]', constructorMap, name);
   return constructorFn;
 }