DevTools: Show preview for ES6 MapIterator, SetIterator in console.

Source/core/inspector/InjectedScriptSource.js

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 1196 matching lines @@
                 return preview;
 
             // Add internal properties to preview.
             var internalProperties = InjectedScriptHost.getInternalProperties(object) || [];
             for (var i = 0; i < internalProperties.length; ++i) {
                 internalProperties[i] = nullifyObjectProto(internalProperties[i]);
                 internalProperties[i].enumerable = true;
             }
             this._appendPropertyDescriptors(preview, internalProperties, propertiesThreshold, secondLevelKeys, isTable);
 
-            if (this.subtype === "map" || this.subtype === "set")
+            if (this.subtype === "map" || this.subtype === "set" || this.subtype === "iterator")
                 this._appendEntriesPreview(object, preview, skipEntriesPreview);
 
         } catch (e) {
             preview.lossless = false;
         }
 
         return preview;
     },
 
     /**
@@ skipping 578 matching lines @@
      */
     _logEvent: function(event)
     {
         inspectedWindow.console.log(event.type, event);
     }
 }
 
 injectedScript._commandLineAPIImpl = new CommandLineAPIImpl();
 return injectedScript;
 })