Add flags and skeleton for profiling process.

chrome/profiling/profiling_main.h

+// Copyright 2017 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 CHROME_PROFILING_PROFILING_MAIN_H_
+#define CHROME_PROFILING_PROFILING_MAIN_H_
+
+namespace base {
+class CommandLine;
+}
+
+namespace profiling {
+
+int ProfilingMain(const base::CommandLine& cmdline);
+
+}  // namespace profiling
+
+#endif  // CHROME_PROFILING_PROFILING_MAIN_H_