Have each SandboxedProcessLauncherDelegate maintain a zygote.

components/nacl/browser/nacl_process_host.cc

Index: components/nacl/browser/nacl_process_host.cc
diff --git a/components/nacl/browser/nacl_process_host.cc b/components/nacl/browser/nacl_process_host.cc
index 41e337a408bb0fd76fb89ad7381449f100fd71f6..614686c7315b1e531c4ac66b275ba7c3b962f06c 100644
--- a/components/nacl/browser/nacl_process_host.cc
+++ b/components/nacl/browser/nacl_process_host.cc
@@ -68,6 +68,7 @@
 #include <netinet/in.h>
 #include <sys/socket.h>
 
+#include "content/public/browser/zygote_handle_linux.h"
 #include "ipc/ipc_channel_posix.h"
 #elif defined(OS_WIN)
 #include <windows.h>
@@ -155,6 +156,10 @@ bool RunningOnWOW64() {
 
 namespace {
 
+#if defined(OS_POSIX) && !defined(OS_ANDROID) && !defined(OS_MACOSX)
+content::ZygoteHandle g_nacl_zygote;
+#endif  // defined(OS_POSIX) && !defined(OS_ANDROID) && !defined(OS_MACOSX)
+
 // NOTE: changes to this class need to be reviewed by the security team.
 class NaClSandboxedProcessLauncherDelegate
     : public content::SandboxedProcessLauncherDelegate {
@@ -181,7 +186,10 @@ class NaClSandboxedProcessLauncherDelegate
     }
   }
 #elif defined(OS_POSIX)
-  bool ShouldUseZygote() override { return true; }
+#if !defined(OS_MACOSX) && !defined(OS_ANDROID)
+  content::ZygoteHandle* GetZygote() override { return &g_nacl_zygote; }
+#endif  // !defined(OS_MACOSX) && !defined(OS_ANDROID)
+
   base::ScopedFD TakeIpcFd() override { return std::move(ipc_fd_); }
 #endif  // OS_WIN
 
@@ -417,6 +425,14 @@ void NaClProcessHost::EarlyStartup() {
   NaClBrowser::GetDelegate()->SetDebugPatterns(nacl_debug_mask);
 }
 
+#if defined(OS_POSIX) && !defined(OS_ANDROID) && !defined(OS_MACOSX)
+// static
+void NaClProcessHost::EarlyZygoteLaunch() {
+  DCHECK(!g_nacl_zygote);
+  g_nacl_zygote = content::CreateZygote();
+}
+#endif  // defined(OS_POSIX) && !defined(OS_ANDROID) && !defined(OS_MACOSX)
+
 // static
 void NaClProcessHost::SetPpapiKeepAliveThrottleForTesting(
     unsigned milliseconds) {