DevTools: Gracefully ignore unknown 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 59 matching lines @@
 
 DebuggerScript.getFunctionScopes = function(fun)
 {
     var mirror = MakeMirror(fun);
     var count = mirror.scopeCount();
     if (count == 0)
         return null;
     var result = [];
     for (var i = 0; i < count; i++) {
         var scopeDetails = mirror.scope(i).details();
-        result[i] = {
+        var scopeObject = DebuggerScript._buildScopeObject(scopeDetails.type(), scopeDetails.object());

[yurys, 2014/11/14 16:08:55]

Why not support the new scope type instead? New scope types are not added often
and we anyways need to support all of them.

+        if (!scopeObject)
+            continue;
+        result.push({
             type: scopeDetails.type(),
-            object: DebuggerScript._buildScopeObject(scopeDetails.type(), scopeDetails.object())
-        };
+            object: scopeObject
+        });
     }
     return result;
 }
 
 DebuggerScript.getCollectionEntries = function(object)
 {
     var mirror = MakeMirror(object, true /* transient */);
     if (mirror.isMap())
         return mirror.entries();
     if (mirror.isSet() || mirror.isIterator()) {
@@ skipping 281 matching lines @@
 
     // Calculated lazily.
     var scopeChain;
     var funcMirror;
     var location;
 
     function lazyScopeChain()
     {
         if (!scopeChain) {
             scopeChain = [];
-            for (var i = 0; i < scopeObjects.length; ++i)
-                scopeChain.push(DebuggerScript._buildScopeObject(scopeTypes[i], scopeObjects[i]));
+            for (var i = 0; i < scopeObjects.length; ++i) {
+                var scopeObject = DebuggerScript._buildScopeObject(scopeDetails.type(), scopeDetails.object());
+                if (scopeObject)
+                    scopeChain.push(scopeObject);
+            }
             scopeObjects = null; // Free for GC.
         }
         return scopeChain;
     }
 
     function ensureFuncMirror()
     {
         if (!funcMirror) {
             funcMirror = MakeMirror(funcObject);
             if (!funcMirror.isFunction())
@@ skipping 142 matching lines @@
         "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;
 })();