Use closure tracer to identify closures that are not passed to Function.apply

sdk/lib/_internal/compiler/implementation/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 48 matching lines @@
     'isNotEmpty',
     'length',
     'clear',
     'containsKey',
     'containsValue',
     '[]=',
     // [keys] only allows key values to escape, which we do not track.
     'keys'
   ]);
 
-abstract class TracerVisitor implements TypeInformationVisitor {
-  final TypeInformation tracedType;
+abstract class TracerVisitor<T extends TypeInformation>
+    implements TypeInformationVisitor {
+  final T tracedType;
   final TypeGraphInferrerEngine inferrer;
   final Compiler compiler;
 
   static const int MAX_ANALYSIS_COUNT = 16;
   final Setlet<Element> analyzedElements = new Setlet<Element>();
 
   TracerVisitor(this.tracedType, inferrer)
       : this.inferrer = inferrer, this.compiler = inferrer.compiler;
 
   // Work list that gets populated with [TypeInformation] that could
@@ skipping 255 matching lines @@
     Element outermost = element.getOutermostEnclosingMemberOrTopLevel();
     return outermost.declaration != element.declaration;
   }
 
   void visitElementTypeInformation(ElementTypeInformation info) {
     Element element = info.element;
     if (element.isParameter()
         && inferrer.isNativeElement(element.enclosingElement)) {
       bailout('Passed to a native method');
     }
-    if (info.isClosurized()) {
+    if (info.isClosurized) {
       bailout('Returned from a closurized method');
     }
     if (isClosure(info.element)) {
       bailout('Returned from a closure');
     }
     if (compiler.backend.isNeededForReflection(info.element)) {
       bailout('Escape in reflection');
     }
+    if (!inferrer.compiler.backend
+        .canBeUsedForGlobalOptimizations(info.element)) {
+      bailout('Escape to code that has special backend treatment');
+    }
     if (isParameterOfListAddingMethod(info.element) ||
         isParameterOfMapAddingMethod(info.element)) {
       // These elements are being handled in
       // [visitDynamicCallSiteTypeInformation].
       return;
     }
     addNewEscapeInformation(info);
   }
 }