diff --git a/devtools/client/fronts/moz.build b/devtools/client/fronts/moz.build
index 03d1b15e29e4..2114d4253710 100644
--- a/devtools/client/fronts/moz.build
+++ b/devtools/client/fronts/moz.build
@@ -1,7 +1,10 @@
+# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
 # 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/.
 
 DevToolsModules(
     'storage.js',
+    'stylesheets.js'
 )
diff --git a/devtools/client/fronts/stylesheets.js b/devtools/client/fronts/stylesheets.js
new file mode 100644
index 000000000000..592de8b82a97
--- /dev/null
+++ b/devtools/client/fronts/stylesheets.js
@@ -0,0 +1,36 @@
+/* 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/. */
+"use strict";
+
+const { Front, FrontClassWithSpec } = require("devtools/server/protocol.js");
+const { originalSourceSpec } = require("devtools/shared/specs/stylesheets.js");
+
+/**
+ * The client-side counterpart for an OriginalSourceActor.
+ */
+const OriginalSourceFront = FrontClassWithSpec(originalSourceSpec, {
+  initialize: function (client, form) {
+    Front.prototype.initialize.call(this, client, form);
+
+    this.isOriginalSource = true;
+  },
+
+  form: function (form, detail) {
+    if (detail === "actorid") {
+      this.actorID = form;
+      return;
+    }
+    this.actorID = form.actor;
+    this._form = form;
+  },
+
+  get href() {
+    return this._form.url;
+  },
+  get url() {
+    return this._form.url;
+  }
+});
+
+exports.OriginalSourceFront = OriginalSourceFront;
diff --git a/devtools/server/actors/stylesheets.js b/devtools/server/actors/stylesheets.js
index 555324115c8c..b2a49a4ab8cf 100644
--- a/devtools/server/actors/stylesheets.js
+++ b/devtools/server/actors/stylesheets.js
@@ -14,11 +14,13 @@ Cu.import("resource://gre/modules/Task.jsm");
 
 const promise = require("promise");
 const events = require("sdk/event/core");
+const {OriginalSourceFront} = require("devtools/client/fronts/stylesheets");
 const protocol = require("devtools/server/protocol");
 const {Arg, Option, method, RetVal, types} = protocol;
 const {LongStringActor, ShortLongString} = require("devtools/server/actors/string");
 const {fetch} = require("devtools/shared/DevToolsUtils");
 const {listenOnce} = require("devtools/shared/async-utils");
+const {originalSourceSpec} = require("devtools/shared/specs/stylesheets");
 const {SourceMapConsumer} = require("source-map");
 
 loader.lazyGetter(this, "CssLogic", () => require("devtools/shared/inspector/css-logic").CssLogic);
@@ -66,9 +68,7 @@ let modifiedStyleSheets = new WeakMap();
  * Actor representing an original source of a style sheet that was specified
  * in a source map.
  */
-var OriginalSourceActor = protocol.ActorClass({
-  typeName: "originalsource",
-
+var OriginalSourceActor = protocol.ActorClassWithSpec(originalSourceSpec, {
   initialize: function(aUrl, aSourceMap, aParentActor) {
     protocol.Actor.prototype.initialize.call(this, null);
 
@@ -110,43 +110,12 @@ var OriginalSourceActor = protocol.ActorClass({
   /**
    * Protocol method to get the text of this source.
    */
-  getText: method(function() {
+  getText: function() {
     return this._getText().then((text) => {
       return new LongStringActor(this.conn, text || "");
     });
-  }, {
-    response: {
-      text: RetVal("longstring")
-    }
-  })
-})
-
-/**
- * The client-side counterpart for an OriginalSourceActor.
- */
-var OriginalSourceFront = protocol.FrontClass(OriginalSourceActor, {
-  initialize: function(client, form) {
-    protocol.Front.prototype.initialize.call(this, client, form);
-
-    this.isOriginalSource = true;
-  },
-
-  form: function(form, detail) {
-    if (detail === "actorid") {
-      this.actorID = form;
-      return;
-    }
-    this.actorID = form.actor;
-    this._form = form;
-  },
-
-  get href() {
-    return this._form.url;
-  },
-  get url() {
-    return this._form.url;
   }
-});
+})
 
 /**
  * A MediaRuleActor lives on the server and provides access to properties
diff --git a/devtools/shared/moz.build b/devtools/shared/moz.build
index d08ed96866c6..b6f6b6dfec45 100644
--- a/devtools/shared/moz.build
+++ b/devtools/shared/moz.build
@@ -22,8 +22,8 @@ DIRS += [
     'qrcode',
     'security',
     'sourcemap',
-    'specs',
     'shims',
+    'specs',
     'touch',
     'transport',
     'webconsole',
diff --git a/devtools/shared/specs/moz.build b/devtools/shared/specs/moz.build
index 5104f375e413..2114d4253710 100644
--- a/devtools/shared/specs/moz.build
+++ b/devtools/shared/specs/moz.build
@@ -5,5 +5,6 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 DevToolsModules(
-    'storage.js'
+    'storage.js',
+    'stylesheets.js'
 )
diff --git a/devtools/shared/specs/stylesheets.js b/devtools/shared/specs/stylesheets.js
new file mode 100644
index 000000000000..61e5a639815f
--- /dev/null
+++ b/devtools/shared/specs/stylesheets.js
@@ -0,0 +1,20 @@
+/* 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/. */
+"use strict";
+
+const { RetVal, generateActorSpec } = require("devtools/server/protocol.js");
+
+const originalSourceSpec = generateActorSpec({
+  typeName: "originalsource",
+
+  methods: {
+    getText: {
+      response: {
+        text: RetVal("longstring")
+      }
+    }
+  }
+});
+
+exports.originalSourceSpec = originalSourceSpec;