Have each SandboxedProcessLauncherDelegate maintain a zygote.

content/public/common/sandboxed_process_launcher_delegate.h

 // Copyright (c) 2012 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_SANDBOXED_PROCESS_LAUNCHER_DELEGATE_H_
 #define CONTENT_PUBLIC_COMMON_SANDBOXED_PROCESS_LAUNCHER_DELEGATE_H_
 
+#include <cstddef>
+
 #include "base/environment.h"
 #include "base/files/scoped_file.h"
 #include "base/process/process.h"
 #include "build/build_config.h"
 #include "content/common/content_export.h"
 #include "content/public/common/sandbox_type.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace sandbox {
 class TargetPolicy;
 }
 
 namespace content {
 
+#if defined(OS_LINUX)
+class ZygoteCommunication;
+using ZygoteHandle = ZygoteCommunication*;
+#else
+using ZygoteHandle = std::nullptr_t;
+#endif
+
 // Allows a caller of StartSandboxedProcess or
 // BrowserChildProcessHost/ChildProcessLauncher to control the sandbox policy,
 // i.e. to loosen it if needed.
 // The methods below will be called on the PROCESS_LAUNCHER thread.
 class CONTENT_EXPORT SandboxedProcessLauncherDelegate {
  public:
   virtual ~SandboxedProcessLauncherDelegate() {}
 
 #if defined(OS_WIN)
   // Override to return true if the process should be launched as an elevated
   // process (which implies no sandbox).
   virtual bool ShouldLaunchElevated();
 
   // By default, the process is launched sandboxed. Override this method to
   // return false if the process should be launched without a sandbox
   // (i.e. through base::LaunchProcess directly).
   virtual bool ShouldSandbox();
 
   // Whether to disable the default policy specified in
   // AddPolicyForSandboxedProcess.
   virtual bool DisableDefaultPolicy();
 
   // Called right before spawning the process. Returns false on failure.
   virtual bool PreSpawnTarget(sandbox::TargetPolicy* policy);
 
   // Called right after the process is launched, but before its thread is run.
   virtual void PostSpawnTarget(base::ProcessHandle process) {}
 
 #elif defined(OS_POSIX)
+#if !defined(OS_MACOSX) && !defined(OS_ANDROID)
   // Override this to return true to use the setuid sandbox.
-  virtual bool ShouldUseZygote();
+  virtual ZygoteHandle* GetZygote();
+#endif  // !defined(OS_MACOSX) && !defined(OS_ANDROID)
 
   // Override this if the process needs a non-empty environment map.
   virtual base::EnvironmentMap GetEnvironment();
 
   // Return the file descriptor for the IPC channel.
   virtual base::ScopedFD TakeIpcFd() = 0;
 #endif
 
   // Returns the SandboxType to enforce on the process, or SANDBOX_TYPE_INVALID
   // for no sandbox policy.
   virtual SandboxType GetSandboxType();
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_SANDBOXED_PROCESS_LAUNCHER_DELEGATE_H_