Revert of [mojo] Use a pipe path to initialise Mojo in elevated utility processes.

mojo/edk/embedder/named_platform_channel_pair.h

-// 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 MOJO_EDK_EMBEDDER_NAMED_PLATFORM_CHANNEL_PAIR_H_
-#define MOJO_EDK_EMBEDDER_NAMED_PLATFORM_CHANNEL_PAIR_H_
-
-#include <string>
-
-#include "base/macros.h"
-#include "base/strings/string16.h"
-#include "build/build_config.h"
-#include "mojo/edk/embedder/scoped_platform_handle.h"
-#include "mojo/edk/system/system_impl_export.h"
-
-namespace base {
-class CommandLine;
-}
-
-namespace mojo {
-namespace edk {
-
-// This is used to create a named bidirectional pipe to connect new child
-// processes. The resulting server handle should be passed to the EDK, and the
-// child end passed as a pipe name on the command line to the child process. The
-// child process can then retrieve the pipe name from the command line and
-// resolve it into a client handle.
-class MOJO_SYSTEM_IMPL_EXPORT NamedPlatformChannelPair {
- public:
-  NamedPlatformChannelPair();
-  ~NamedPlatformChannelPair();
-
-  // Note: It is NOT acceptable to use this handle as a generic pipe channel. It
-  // MUST be passed to mojo::edk::ChildProcessLaunched() only.
-  ScopedPlatformHandle PassServerHandle();
-
-  // To be called in the child process, after the parent process called
-  // |PrepareToPassClientHandleToChildProcess()| and launched the child (using
-  // the provided data), to create a client handle connected to the server
-  // handle (in the parent process).
-  static ScopedPlatformHandle PassClientHandleFromParentProcess(
-      const base::CommandLine& command_line);
-
-  // Prepares to pass the client channel to a new child process, to be launched
-  // using |LaunchProcess()| (from base/launch.h). Modifies |*command_line| and
-  // |*handle_passing_info| as needed.
-  // Note: For Windows, this method only works on Vista and later.
-  void PrepareToPassClientHandleToChildProcess(
-      base::CommandLine* command_line) const;
-
- private:
-  ScopedPlatformHandle server_handle_;
-
-#if defined(OS_WIN)
-  base::string16 pipe_name_;
-#endif
-
-  DISALLOW_COPY_AND_ASSIGN(NamedPlatformChannelPair);
-};
-
-}  // namespace edk
-}  // namespace mojo
-
-#endif  // MOJO_EDK_EMBEDDER_NAMED_PLATFORM_CHANNEL_PAIR_H_