Have each SandboxedProcessLauncherDelegate maintain a zygote.

content/browser/utility_process_host_impl.cc

 // 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.
 
 #include "content/browser/utility_process_host_impl.h"
 
 #include <utility>
 
 #include "base/base_switches.h"
 #include "base/bind.h"
@@ skipping 68 matching lines @@
 
     base::FilePath exposed_files = exposed_dir_.AppendASCII("*");
     result = policy->AddRule(sandbox::TargetPolicy::SUBSYS_FILES,
                              sandbox::TargetPolicy::FILES_ALLOW_ANY,
                              exposed_files.value().c_str());
     return result == sandbox::SBOX_ALL_OK;
   }
 
 #elif defined(OS_POSIX)
 
-  bool ShouldUseZygote() override {
-    return !no_sandbox_ && exposed_dir_.empty();
+  ZygoteHandle* GetZygote() override {
+    if (!no_sandbox_ && exposed_dir_.empty()) {
+      static ZygoteHandle zygote;
+      return &zygote;
+    }
+    return nullptr;
   }
   base::EnvironmentMap GetEnvironment() override { return env_; }
   base::ScopedFD TakeIpcFd() override { return std::move(ipc_fd_); }
 #endif  // OS_WIN
 
   SandboxType GetSandboxType() override {
     return SANDBOX_TYPE_UTILITY;
   }
 
  private:
@@ skipping 276 matching lines @@
     if (RenderProcessHost::run_renderer_in_process())
       handle = base::GetCurrentProcessHandle();
     else
       handle = process_->GetData().handle;
 
     mojo_application_host_->Activate(this, handle);
   }
 }
 
 }  // namespace content