Have each SandboxedProcessLauncherDelegate maintain a zygote.

content/browser/ppapi_plugin_process_host.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/ppapi_plugin_process_host.h"
 
 #include <string>
 #include <utility>
 
 #include "base/base_switches.h"
@@ skipping 74 matching lines @@
     const base::string16& sid =
         GetContentClient()->browser()->GetAppContainerSidForSandboxType(
             GetSandboxType());
     if (!sid.empty())
       AddAppContainerPolicy(policy, sid.c_str());
 
     return true;
   }
 
 #elif defined(OS_POSIX)
-  bool ShouldUseZygote() override {
+  ZygoteHandle* GetZygote() override {
     const base::CommandLine& browser_command_line =
         *base::CommandLine::ForCurrentProcess();
     base::CommandLine::StringType plugin_launcher = browser_command_line
         .GetSwitchValueNative(switches::kPpapiPluginLauncher);
-    return !is_broker_ && plugin_launcher.empty();
+    if (!is_broker_ && plugin_launcher.empty()) {

[mdempsky, 2015/12/22 21:21:33]

Nit: It's pretty negligible here, but in general I suggest trying to arrange if
statements to minimize how much code needs to be intended.  In this case, I
would write:

    if (is_broker_ || !plugin_launcher.empty())
      return nullptr;

    static ZygoteHandle zygote;
    return &zygote;

(Same goes for the other GetZygote functions too.)

[Greg K, 2016/01/05 21:42:13]

Done.

+      static ZygoteHandle zygote;
+      return &zygote;
+    }
+    return nullptr;
   }
   base::ScopedFD TakeIpcFd() override { return std::move(ipc_fd_); }
 #endif  // OS_WIN
 
   SandboxType GetSandboxType() override {
     return SANDBOX_TYPE_PPAPI;
   }
 
  private:
   const PepperPluginInfo& info_;
@@ skipping 401 matching lines @@
   // sent_requests_ queue should be the one that the plugin just created.
   Client* client = sent_requests_.front();
   sent_requests_.pop();
 
   const ChildProcessData& data = process_->GetData();
   client->OnPpapiChannelOpened(channel_handle, base::GetProcId(data.handle),
                                data.id);
 }
 
 }  // namespace content