Have each SandboxedProcessLauncherDelegate maintain a zygote.

content/content_browser.gypi

 # 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base_static',
     '../components/url_formatter/url_formatter.gyp:url_formatter',
     '../crypto/crypto.gyp:crypto',
     '../device/battery/battery.gyp:device_battery',
@@ skipping 1552 matching lines @@
       'browser/webui/url_data_manager_backend.h',
       'browser/webui/url_data_source_impl.cc',
       'browser/webui/url_data_source_impl.h',
       'browser/webui/web_ui_controller_factory_registry.cc',
       'browser/webui/web_ui_controller_factory_registry.h',
       'browser/webui/web_ui_data_source_impl.cc',
       'browser/webui/web_ui_data_source_impl.h',
       'browser/webui/web_ui_impl.cc',
       'browser/webui/web_ui_impl.h',
       'browser/webui/web_ui_message_handler.cc',
+      'browser/zygote_host/zygote_communication_linux.h',
+      'browser/zygote_host/zygote_communication_linux.cc',
       'browser/zygote_host/zygote_host_impl_linux.cc',
       'browser/zygote_host/zygote_host_impl_linux.h',
       'zygote/zygote_linux.cc',
       'zygote/zygote_linux.h',
       'zygote/zygote_main_linux.cc',
     ],
     'android_browser_sources': [
       'browser/android/java/gin_java_bound_object.cc',
       'browser/android/java/gin_java_bound_object.h',
       'browser/android/java/gin_java_bound_object_delegate.cc',
@@ skipping 633 matching lines @@
     ['enable_webvr==1 and OS=="android"', {
       'sources': [
         'browser/vr/android/cardboard/cardboard_vr_device.cc',
         'browser/vr/android/cardboard/cardboard_vr_device.h',
         'browser/vr/android/cardboard/cardboard_vr_device_provider.cc',
         'browser/vr/android/cardboard/cardboard_vr_device_provider.h',
       ],
     }],
   ],
 }