Mojo: Add GetMinimumLogLevel() to the logger interface.

mojo/public/cpp/environment/lib/default_logger_internal.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_ENVIRONMENT_LIB_DEFAULT_LOGGER_INTERNAL_H_
+#define MOJO_PUBLIC_CPP_ENVIRONMENT_LIB_DEFAULT_LOGGER_INTERNAL_H_
+
+#include "mojo/public/c/environment/logger.h"
+
+namespace mojo {
+namespace internal {
+
+// Sets the minimum log level (which will always be at most
+// |MOJO_LOG_LEVEL_FATAL|).
+void SetMinimumLogLevel(MojoLogLevel minimum_log_level);
+
+}  // namespace internal
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_ENVIRONMENT_LIB_DEFAULT_LOGGER_INTERNAL_H_