Properly detect cycles in V8ValueConverter, current impl is too strict.

content/child/v8_value_converter_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_CHILD_V8_VALUE_CONVERTER_IMPL_H_
 #define CONTENT_CHILD_V8_VALUE_CONVERTER_IMPL_H_
 
 #include <map>
 
 #include "base/compiler_specific.h"
@@ skipping 23 matching lines @@
   v8::Local<v8::Value> ToV8Value(
       const base::Value* value,
       v8::Local<v8::Context> context) const override;
   base::Value* FromV8Value(v8::Local<v8::Value> value,
                            v8::Local<v8::Context> context) const override;
 
  private:
   friend class ScopedAvoidIdentityHashForTesting;
 
   class FromV8ValueState;
+  class ScopedUniquenessGuard;
 
   v8::Local<v8::Value> ToV8ValueImpl(v8::Isolate* isolate,
                                      v8::Local<v8::Object> creation_context,
                                      const base::Value* value) const;
   v8::Local<v8::Value> ToV8Array(v8::Isolate* isolate,
                                   v8::Local<v8::Object> creation_context,
                                   const base::ListValue* list) const;
   v8::Local<v8::Value> ToV8Object(
       v8::Isolate* isolate,
       v8::Local<v8::Object> creation_context,
@@ skipping 35 matching lines @@
 
   // Strategy object that changes the converter's behavior.
   Strategy* strategy_;
 
   DISALLOW_COPY_AND_ASSIGN(V8ValueConverterImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_V8_VALUE_CONVERTER_IMPL_H_