Revert of Have each SandboxedProcessLauncherDelegate maintain a zygote.

content/browser/zygote_host/zygote_communication_linux.h

-// Copyright 2015 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_BROWSER_ZYGOTE_HOST_ZYGOTE_COMMUNICATION_LINUX_H_
-#define CONTENT_BROWSER_ZYGOTE_HOST_ZYGOTE_COMMUNICATION_LINUX_H_
-
-#include <set>
-#include <vector>
-
-#include "base/process/kill.h"
-#include "base/synchronization/lock.h"
-#include "content/common/content_export.h"
-#include "content/public/browser/file_descriptor_info.h"
-
-namespace content {
-
-class CONTENT_EXPORT ZygoteCommunication {
- public:
-  ZygoteCommunication();
-  ~ZygoteCommunication();
-
-  void Init();
-
-  // Tries to start a process of type indicated by process_type.
-  // Returns its pid on success, otherwise base::kNullProcessHandle;
-  pid_t ForkRequest(const std::vector<std::string>& command_line,
-                    scoped_ptr<FileDescriptorInfo> mapping,
-                    const std::string& process_type);
-
-  void EnsureProcessTerminated(pid_t process);
-
-  // Should be called every time a Zygote child died.
-  void ZygoteChildDied(pid_t process);
-
-  // Get the termination status (and, optionally, the exit code) of
-  // the process. |exit_code| is set to the exit code of the child
-  // process. (|exit_code| may be NULL.)
-  // Unfortunately the Zygote can not accurately figure out if a process
-  // is already dead without waiting synchronously for it.
-  // |known_dead| should be set to true when we already know that the process
-  // is dead. When |known_dead| is false, processes could be seen as
-  // still running, even when they're not. When |known_dead| is true, the
-  // process will be SIGKILL-ed first (which should have no effect if it was
-  // really dead). This is to prevent a waiting waitpid() from blocking in
-  // a single-threaded Zygote. See crbug.com/157458.
-  base::TerminationStatus GetTerminationStatus(base::ProcessHandle handle,
-                                               bool known_dead,
-                                               int* exit_code);
-
-  // Returns the sandbox status of this zygote.
-  int GetSandboxStatus();
-
- private:
-  // Whether we should use the namespace sandbox instead of the setuid sandbox.
-  bool ShouldUseNamespaceSandbox();
-
-  // Should be called every time a Zygote child is born.
-  void ZygoteChildBorn(pid_t process);
-
-  // Read the reply from the zygote.
-  ssize_t ReadReply(void* buf, size_t buf_len);
-
-  // Sends |data| to the zygote via |control_fd_|.  If |fds| is non-NULL, the
-  // included file descriptors will also be passed.  The caller is responsible
-  // for acquiring |control_lock_|.
-  bool SendMessage(const base::Pickle& data, const std::vector<int>* fds);
-
-  // Get the sandbox status from the zygote.
-  ssize_t ReadSandboxStatus();
-
-  int control_fd_;  // the socket to the zygote.
-  // A lock protecting all communication with the zygote. This lock must be
-  // acquired before sending a command and released after the result has been
-  // received.
-  base::Lock control_lock_;
-  // The pid of the zygote.
-  pid_t pid_;
-  // The list of running zygote children.
-  std::set<pid_t> list_of_running_zygote_children_;
-  // The lock to guard the list of running zygote children.
-  base::Lock child_tracking_lock_;
-  int sandbox_status_;
-  bool have_read_sandbox_status_word_;
-  bool use_suid_sandbox_for_adj_oom_score_;
-  // Set to true when the zygote is initialized successfully.
-  bool init_;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_ZYGOTE_HOST_ZYGOTE_COMMUNICATION_LINUX_H_