--- a/browser/extensions/pdfjs/content/PdfJs.jsm
+++ b/browser/extensions/pdfjs/content/PdfJs.jsm
@@ -12,18 +12,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 "use strict";
 
 var EXPORTED_SYMBOLS = ["PdfJs"];
 
-const Cm = Components.manager;
-
 const PREF_PREFIX = "pdfjs";
 const PREF_DISABLED = PREF_PREFIX + ".disabled";
 const PREF_MIGRATION_VERSION = PREF_PREFIX + ".migrationVersion";
 const PREF_PREVIOUS_ACTION = PREF_PREFIX + ".previousHandler.preferredAction";
 const PREF_PREVIOUS_ASK = PREF_PREFIX +
                           ".previousHandler.alwaysAskBeforeHandling";
 const PREF_DISABLED_PLUGIN_TYPES = "plugin.disable_full_page_plugin_for_types";
 const PREF_ENABLED_CACHE_STATE = PREF_PREFIX + ".enabledCache.state";
@@ -46,16 +44,18 @@ XPCOMUtils.defineLazyServiceGetter(Svc, 
                                    "@mozilla.org/plugin/host;1",
                                    "nsIPluginHost");
 ChromeUtils.defineModuleGetter(this, "PdfjsChromeUtils",
                                "resource://pdf.js/PdfjsChromeUtils.jsm");
 ChromeUtils.defineModuleGetter(this, "PdfjsContentUtils",
                                "resource://pdf.js/PdfjsContentUtils.jsm");
 ChromeUtils.defineModuleGetter(this, "PdfJsDefaultPreferences",
   "resource://pdf.js/PdfJsDefaultPreferences.jsm");
+ChromeUtils.defineModuleGetter(this, "PdfJsRegistration",
+  "resource://pdf.js/PdfJsRegistration.jsm");
 
 function getBoolPref(aPref, aDefaultValue) {
   try {
     return Services.prefs.getBoolPref(aPref);
   } catch (ex) {
     return aDefaultValue;
   }
 }
@@ -90,50 +90,18 @@ function initializeDefaultPreferences() 
         break;
       case "string":
         defaultBranch.setCharPref(key, defaultValue);
         break;
     }
   }
 }
 
-// Register/unregister a constructor as a factory.
-function Factory() {}
-Factory.prototype = {
-  register: function register(targetConstructor) {
-    var proto = targetConstructor.prototype;
-    this._classID = proto.classID;
-
-    var factory = XPCOMUtils._getFactory(targetConstructor);
-    this._factory = factory;
-
-    var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
-    registrar.registerFactory(proto.classID, proto.classDescription,
-                              proto.contractID, factory);
-
-    if (proto.classID2) {
-      this._classID2 = proto.classID2;
-      registrar.registerFactory(proto.classID2, proto.classDescription,
-                                proto.contractID2, factory);
-    }
-  },
-
-  unregister: function unregister() {
-    var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
-    registrar.unregisterFactory(this._classID, this._factory);
-    if (this._classID2) {
-      registrar.unregisterFactory(this._classID2, this._factory);
-    }
-    this._factory = null;
-  },
-};
-
 var PdfJs = {
   QueryInterface: ChromeUtils.generateQI([Ci.nsIObserver]),
-  _registered: false,
   _initialized: false,
 
   init: function init(remote) {
     if (Services.appinfo.processType !==
         Services.appinfo.PROCESS_TYPE_DEFAULT) {
       throw new Error("PdfJs.init should only get called " +
                       "in the parent process.");
     }
@@ -328,30 +296,16 @@ var PdfJs = {
       }
 
       Services.prefs.setBoolPref(PREF_ENABLED_CACHE_INITIALIZED, true);
     }
     return Services.prefs.getBoolPref(PREF_ENABLED_CACHE_STATE, true);
   },
 
   ensureRegistered: function ensureRegistered() {
-    if (this._registered) {
-      return;
-    }
-    this._pdfStreamConverterFactory = new Factory();
-    ChromeUtils.import("resource://pdf.js/PdfStreamConverter.jsm");
-    this._pdfStreamConverterFactory.register(PdfStreamConverter);
-
-    this._registered = true;
+    PdfJsRegistration.ensureRegistered();
   },
 
   ensureUnregistered: function ensureUnregistered() {
-    if (!this._registered) {
-      return;
-    }
-    this._pdfStreamConverterFactory.unregister();
-    Cu.unload("resource://pdf.js/PdfStreamConverter.jsm");
-    delete this._pdfStreamConverterFactory;
-
-    this._registered = false;
+    PdfJsRegistration.ensureUnregistered();
   },
 };
 

new file mode 100644
--- /dev/null
+++ b/browser/extensions/pdfjs/content/PdfJsRegistration.jsm
@@ -0,0 +1,81 @@
+/* Copyright 2018 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+"use strict";
+
+var EXPORTED_SYMBOLS = ["PdfJsRegistration"];
+
+const Cm = Components.manager;
+
+ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
+
+
+// Register/unregister a constructor as a factory.
+function Factory() {}
+Factory.prototype = {
+  register: function register(targetConstructor) {
+    var proto = targetConstructor.prototype;
+    this._classID = proto.classID;
+
+    var factory = XPCOMUtils._getFactory(targetConstructor);
+    this._factory = factory;
+
+    var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
+    registrar.registerFactory(proto.classID, proto.classDescription,
+                              proto.contractID, factory);
+
+    if (proto.classID2) {
+      this._classID2 = proto.classID2;
+      registrar.registerFactory(proto.classID2, proto.classDescription,
+                                proto.contractID2, factory);
+    }
+  },
+
+  unregister: function unregister() {
+    var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
+    registrar.unregisterFactory(this._classID, this._factory);
+    if (this._classID2) {
+      registrar.unregisterFactory(this._classID2, this._factory);
+    }
+    this._factory = null;
+  },
+};
+
+var PdfJsRegistration = {
+  _registered: false,
+
+  ensureRegistered: function ensureRegistered() {
+    if (this._registered) {
+      return;
+    }
+    this._pdfStreamConverterFactory = new Factory();
+    ChromeUtils.import("resource://pdf.js/PdfStreamConverter.jsm");
+    this._pdfStreamConverterFactory.register(PdfStreamConverter);
+
+    this._registered = true;
+  },
+
+  ensureUnregistered: function ensureUnregistered() {
+    if (!this._registered) {
+      return;
+    }
+    this._pdfStreamConverterFactory.unregister();
+    Cu.unload("resource://pdf.js/PdfStreamConverter.jsm");
+    delete this._pdfStreamConverterFactory;
+
+    this._registered = false;
+  },
+
+};

--- a/browser/extensions/pdfjs/content/PdfjsContentUtils.jsm
+++ b/browser/extensions/pdfjs/content/PdfjsContentUtils.jsm
@@ -113,21 +113,21 @@ var PdfjsContentUtils = {
   },
 
   receiveMessage(aMsg) {
     switch (aMsg.name) {
       case "PDFJS:Child:updateSettings":
         // Only react to this if we are remote.
         if (Services.appinfo.processType ===
             Services.appinfo.PROCESS_TYPE_CONTENT) {
-          let jsm = "resource://pdf.js/PdfJs.jsm";
-          let pdfjs = ChromeUtils.import(jsm, {}).PdfJs;
+          let jsm = "resource://pdf.js/PdfJsRegistration.jsm";
+          let pdfjsr = ChromeUtils.import(jsm, {}).PdfJsRegistration;
           if (aMsg.data.enabled) {
-            pdfjs.ensureRegistered();
+            pdfjsr.ensureRegistered();
           } else {
-            pdfjs.ensureUnregistered();
+            pdfjsr.ensureUnregistered();
           }
         }
         break;
     }
   },
 };
 

--- a/browser/extensions/pdfjs/content/pdfjschildbootstrap-enabled.js
+++ b/browser/extensions/pdfjs/content/pdfjschildbootstrap-enabled.js
@@ -17,14 +17,14 @@
 
 /*
  * pdfjschildbootstrap-enabled.js loads into the content process to
  * take care of initializing our built-in version of pdfjs when
  * running remote. It will only be run when PdfJs.enable is true.
  */
 
 ChromeUtils.import("resource://gre/modules/Services.jsm");
-ChromeUtils.import("resource://pdf.js/PdfJs.jsm");
+ChromeUtils.import("resource://pdf.js/PdfJsRegistration.jsm");
 
 if (Services.appinfo.processType === Services.appinfo.PROCESS_TYPE_CONTENT) {
   // register various pdfjs factories that hook us into content loading.
-  PdfJs.ensureRegistered();
+  PdfJsRegistration.ensureRegistered();
 }