Limit Mojo messages recursion depth

mojo/public/cpp/bindings/lib/validation_errors.h

 // Copyright 2014 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_VALIDATION_ERRORS_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_VALIDATION_ERRORS_H_
 
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 52 matching lines @@
   // Two parallel arrays which are supposed to represent a map have different
   // lengths.
   VALIDATION_ERROR_DIFFERENT_SIZED_ARRAYS_IN_MAP,
   // Attempted to deserialize a tagged union with an unknown tag.
   VALIDATION_ERROR_UNKNOWN_UNION_TAG,
   // A value of a non-extensible enum type is unknown.
   VALIDATION_ERROR_UNKNOWN_ENUM_VALUE,
   // Message deserialization failure, for example due to rejection by custom
   // validation logic.
   VALIDATION_ERROR_DESERIALIZATION_FAILED,
+  // The message contains a too deeply nested value, for example a recursively
+  // defined field which runtime value is too large.
+  VALIDATION_ERROR_MAX_RECURSION_DEPTH,
 };
 
 const char* ValidationErrorToString(ValidationError error);
 
 void ReportValidationError(ValidationContext* context,
                            ValidationError error,
                            const char* description = nullptr);
 
 void ReportValidationErrorForMessage(
     mojo::Message* message,
@@ skipping 55 matching lines @@
 //
 // In non-debug build, does nothing (not even compiling |condition|).
 #define MOJO_INTERNAL_DLOG_SERIALIZATION_WARNING(condition, error,    \
                                                  description)         \
   DLOG_IF(FATAL, (condition) && !ReportSerializationWarning(error))   \
       << "The outgoing message will trigger "                         \
       << ValidationErrorToString(error) << " at the receiving side (" \
       << description << ").";
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_VALIDATION_ERRORS_H_