--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -897,19 +897,20 @@ nsXULAppInfo::GetWidgetToolkit(nsACStrin
                 "GeckoProcessType in nsXULAppAPI.h not synchronized with nsIXULRuntime.idl");
 
 SYNC_ENUMS(DEFAULT, Default)
 SYNC_ENUMS(PLUGIN, Plugin)
 SYNC_ENUMS(CONTENT, Content)
 SYNC_ENUMS(IPDLUNITTEST, IPDLUnitTest)
 SYNC_ENUMS(GMPLUGIN, GMPlugin)
 SYNC_ENUMS(GPU, GPU)
+SYNC_ENUMS(PDFIUM, PDFium)
 
 // .. and ensure that that is all of them:
-static_assert(GeckoProcessType_GPU + 1 == GeckoProcessType_End,
+static_assert(GeckoProcessType_PDFium + 1 == GeckoProcessType_End,
               "Did not find the final GeckoProcessType");
 
 NS_IMETHODIMP
 nsXULAppInfo::GetProcessType(uint32_t* aResult)
 {
   NS_ENSURE_ARG_POINTER(aResult);
   *aResult = XRE_GetProcessType();
   return NS_OK;

--- a/toolkit/xre/nsEmbedFunctions.cpp
+++ b/toolkit/xre/nsEmbedFunctions.cpp
@@ -111,16 +111,20 @@
 
 using mozilla::_ipdltest::IPDLUnitTestProcessChild;
 #endif  // ifdef MOZ_IPDL_TESTS
 
 #ifdef MOZ_JPROF
 #include "jprof.h"
 #endif
 
+#if defined(XP_WIN) && defined(MOZ_ENABLE_SKIA_PDF)
+#include "mozilla/widget/PDFiumProcessChild.h"
+#endif
+
 using namespace mozilla;
 
 using mozilla::ipc::BrowserProcessSubThread;
 using mozilla::ipc::GeckoChildProcessHost;
 using mozilla::ipc::IOThreadChild;
 using mozilla::ipc::ProcessChild;
 using mozilla::ipc::ScopedXREEmbed;
 
@@ -600,16 +604,17 @@ XRE_InitChildProcess(int aArgc,
   MessageLoop::Type uiLoopType;
   switch (XRE_GetProcessType()) {
   case GeckoProcessType_Content:
   case GeckoProcessType_GPU:
       // Content processes need the XPCOM/chromium frankenventloop
       uiLoopType = MessageLoop::TYPE_MOZILLA_CHILD;
       break;
   case GeckoProcessType_GMPlugin:
+  case GeckoProcessType_PDFium:
       uiLoopType = MessageLoop::TYPE_DEFAULT;
       break;
   default:
       uiLoopType = MessageLoop::TYPE_UI;
       break;
   }
 
   {
@@ -647,16 +652,21 @@ XRE_InitChildProcess(int aArgc,
         MOZ_CRASH("rebuild with --enable-ipdl-tests");
 #endif
         break;
 
       case GeckoProcessType_GMPlugin:
         process = new gmp::GMPProcessChild(parentPID);
         break;
 
+#if defined(XP_WIN) && defined(MOZ_ENABLE_SKIA_PDF)
+      case GeckoProcessType_PDFium:
+        process = new widget::PDFiumProcessChild(parentPID);
+        break;
+#endif
       case GeckoProcessType_GPU:
         process = new gfx::GPUProcessImpl(parentPID);
         break;
 
       default:
         MOZ_CRASH("Unknown main thread class");
       }
 

new file mode 100644
--- /dev/null
+++ b/widget/windows/PDFiumProcessChild.cpp
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "PDFiumProcessChild.h"
+
+#include "mozilla/ipc/IOThreadChild.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/ContentParent.h"
+
+using mozilla::ipc::IOThreadChild;
+
+namespace mozilla {
+namespace widget {
+
+PDFiumProcessChild::PDFiumProcessChild(ProcessId aParentPid)
+  : ProcessChild(aParentPid)
+{
+}
+
+PDFiumProcessChild::~PDFiumProcessChild()
+{
+}
+
+bool
+PDFiumProcessChild::Init(int aArgc, char* aArgv[])
+{
+  BackgroundHangMonitor::Startup();
+  mPDFiumActor.Init(ParentPid(),IOThreadChild::message_loop(),
+                    IOThreadChild::channel());
+
+  return true;
+}
+
+void
+PDFiumProcessChild::CleanUp()
+{
+  BackgroundHangMonitor::Shutdown();
+}
+
+} // namespace widget
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/widget/windows/PDFiumProcessChild.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef PDFIUMPROCESSCHILD_H_
+#define PDFIUMPROCESSCHILD_H_
+
+#include "mozilla/ipc/ProcessChild.h"
+#include "PDFiumChild.h"
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * Contains the PDFiumChild object that facilitates IPC communication to/from
+ * the instance of the PDFium library that is run in this process.
+ */
+class PDFiumProcessChild final : public mozilla::ipc::ProcessChild
+{
+protected:
+  typedef mozilla::ipc::ProcessChild ProcessChild;
+
+public:
+  explicit PDFiumProcessChild(ProcessId aParentPid);
+  ~PDFiumProcessChild();
+
+  // ProcessChild functions.
+  bool Init(int aArgc, char* aArgv[]) override;
+  void CleanUp() override;
+
+private:
+  DISALLOW_COPY_AND_ASSIGN(PDFiumProcessChild);
+
+  PDFiumChild mPDFiumActor;
+};
+
+} // namespace widget
+} // namespace mozilla
+
+#endif // PDFIUMPROCESSCHILD_H_

new file mode 100644
--- /dev/null
+++ b/widget/windows/PDFiumProcessParent.cpp
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "PDFiumProcessParent.h"
+#include "nsIRunnable.h"
+#if defined(XP_WIN) && defined(MOZ_SANDBOX)
+#include "WinUtils.h"
+#endif
+#include "nsDeviceContextSpecWin.h"
+#include "PDFiumParent.h"
+
+using mozilla::ipc::GeckoChildProcessHost;
+
+namespace mozilla {
+namespace widget {
+
+PDFiumProcessParent::PDFiumProcessParent()
+  : GeckoChildProcessHost(GeckoProcessType_PDFium)
+{
+  MOZ_COUNT_CTOR(PDFiumProcessParent);
+}
+
+PDFiumProcessParent::~PDFiumProcessParent()
+{
+  MOZ_COUNT_DTOR(PDFiumProcessParent);
+}
+
+bool
+PDFiumProcessParent::Launch()
+{
+  return SyncLaunch();
+}
+
+void
+PDFiumProcessParent::Delete()
+{
+}
+
+} // namespace widget
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/widget/windows/PDFiumProcessParent.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: sw=4 ts=4 et :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef PDFIUMPROCESSPARENT_H
+#define PDFIUMPROCESSPARENT_H
+
+#include "chrome/common/child_process_host.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
+
+class nsIRunnable;
+
+namespace mozilla {
+namespace widget {
+
+class PDFiumProcessParent final : public mozilla::ipc::GeckoChildProcessHost
+{
+public:
+  PDFiumProcessParent();
+  ~PDFiumProcessParent();
+
+  bool Launch();
+
+  void Delete();
+
+  bool CanShutdown() override { return true; }
+
+private:
+
+  DISALLOW_COPY_AND_ASSIGN(PDFiumProcessParent);
+};
+
+} // namespace widget
+} // namespace mozilla
+
+#endif // ifndef PDFIUMPROCESSPARENT_H

--- a/widget/windows/moz.build
+++ b/widget/windows/moz.build
@@ -21,16 +21,17 @@ EXPORTS += [
 EXPORTS.mozilla.widget += [
     'AudioSession.h',
     'CompositorWidgetChild.h',
     'CompositorWidgetParent.h',
     'InProcessWinCompositorWidget.h',
     'PDFiumChild.h',
     'PDFiumEngineShim.h',
     'PDFiumParent.h',
+    'PDFiumProcessChild.h',
     'PDFViaEMFPrintHelper.h',
     'WinCompositorWidget.h',
     'WinMessages.h',
     'WinModifierKeyState.h',
     'WinNativeEventData.h',
 ]
 
 UNIFIED_SOURCES += [
@@ -103,16 +104,18 @@ if CONFIG['MOZ_ENABLE_SKIA_PDF']:
     DIRS += ['/modules/pdfium']
     IPDL_SOURCES += [
         'PPDFium.ipdl',
     ]
     UNIFIED_SOURCES += [
         'PDFiumChild.cpp',
         'PDFiumEngineShim.cpp',
         'PDFiumParent.cpp',
+        'PDFiumProcessChild.cpp',
+        'PDFiumProcessParent.cpp',
         'PDFViaEMFPrintHelper.cpp',
         'WindowsEMF.cpp',
     ]
 
 if CONFIG['NS_ENABLE_TSF']:
     SOURCES += [
         'TSFTextStore.cpp',
     ]

--- a/xpcom/build/nsXULAppAPI.h
+++ b/xpcom/build/nsXULAppAPI.h
@@ -369,28 +369,29 @@ enum GeckoProcessType
   GeckoProcessType_Plugin,
   GeckoProcessType_Content,
 
   GeckoProcessType_IPDLUnitTest,
 
   GeckoProcessType_GMPlugin, // Gecko Media Plugin
 
   GeckoProcessType_GPU,      // GPU and compositor process
-
+  GeckoProcessType_PDFium,   // Gecko PDFium process
   GeckoProcessType_End,
   GeckoProcessType_Invalid = GeckoProcessType_End
 };
 
 static const char* const kGeckoProcessTypeString[] = {
   "default",
   "plugin",
   "tab",
   "ipdlunittest",
   "geckomediaplugin",
-  "gpu"
+  "gpu",
+  "pdfium"
 };
 
 static_assert(MOZ_ARRAY_LENGTH(kGeckoProcessTypeString) ==
               GeckoProcessType_End,
               "Array length mismatch");
 
 XRE_API(const char*,
         XRE_ChildProcessTypeToString, (GeckoProcessType aProcessType))

--- a/xpcom/system/nsIXULRuntime.idl
+++ b/xpcom/system/nsIXULRuntime.idl
@@ -71,16 +71,17 @@ interface nsIXULRuntime : nsISupports
    * The legal values of processType.
    */
   const unsigned long PROCESS_TYPE_DEFAULT = 0;
   const unsigned long PROCESS_TYPE_PLUGIN = 1;
   const unsigned long PROCESS_TYPE_CONTENT = 2;
   const unsigned long PROCESS_TYPE_IPDLUNITTEST = 3;
   const unsigned long PROCESS_TYPE_GMPLUGIN = 4;
   const unsigned long PROCESS_TYPE_GPU = 5;
+  const unsigned long PROCESS_TYPE_PDFIUM = 6;
 
   /**
    * The type of the caller's process.  Returns one of the values above.
    */
   readonly attribute unsigned long processType;
 
   /**
    * The system process ID of the caller's process.