DevTools: Support harmony variable scopes.

Source/bindings/core/v8/DebuggerScript.js

 /*
  * Copyright (C) 2010 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 508 matching lines @@
     };
 }
 
 DebuggerScript._buildScopeObject = function(scopeType, scopeObject)
 {
     var result;
     switch (scopeType) {
     case ScopeType.Local:
     case ScopeType.Closure:
     case ScopeType.Catch:
+    case ScopeType.Block:
+    case ScopeType.Script:
         // For transient objects we create a "persistent" copy that contains
         // the same properties.
         // Reset scope object prototype to null so that the proto properties
         // don't appear in the local scope section.
+        var properties = MakeMirror(scopeObject, true /* transient */).properties();
+        // Almost always Script scope will be empty, so just filter out that noise.
+        // Also drop empty Block scopes, should we get any.
+        if (!properties.length && (scopeType === ScopeType.Script || scopeType === ScopeType.Block))
+            break;
         result = { __proto__: null };
-        var properties = MakeMirror(scopeObject, true /* transient */).properties();
         for (var j = 0; j < properties.length; j++) {
             var name = properties[j].name();
             if (name.charAt(0) === ".")
                 continue; // Skip internal variables like ".arguments"
             result[name] = properties[j].value_;
         }
         break;
     case ScopeType.Global:
     case ScopeType.With:
         result = scopeObject;
         break;
-    case ScopeType.Block:
-        // Unsupported yet. Mustn't be reachable.
-        break;
     }
     return result;
 }
 
 DebuggerScript.getPromiseDetails = function(eventData)
 {
     return {
         "promise": eventData.promise().value(),
         "parentPromise": eventData.parentPromise().value(),
         "status": eventData.status()
     };
 }
 
 // We never resolve Mirror by its handle so to avoid memory leaks caused by Mirrors in the cache we disable it.
 ToggleMirrorCache(false);
 
 return DebuggerScript;
 })();