Revert of Have each SandboxedProcessLauncherDelegate maintain a zygote.

content/public/common/zygote_handle.h

Index: content/public/common/zygote_handle.h
diff --git a/content/public/common/zygote_handle.h b/content/public/common/zygote_handle.h
deleted file mode 100644
index 9aa07c4245450e9ed6bba2f0c82aaf9a9d3937bb..0000000000000000000000000000000000000000
--- a/content/public/common/zygote_handle.h
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2016 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_PUBLIC_COMMON_ZYGOTE_HANDLE_H_
-#define CONTENT_PUBLIC_COMMON_ZYGOTE_HANDLE_H_
-
-#include <cstddef>
-
-#include "build/build_config.h"
-
-namespace content {
-
-#if defined(OS_POSIX) && !defined(OS_ANDROID) && !defined(OS_MACOSX)
-class ZygoteCommunication;
-using ZygoteHandle = ZygoteCommunication*;
-#else
-using ZygoteHandle = std::nullptr_t;
-#endif
-
-}  // namespace content
-
-#endif  // CONTENT_PUBLIC_COMMON_ZYGOTE_HANDLE_H_