diff -r 000000000000 -r 6474c204b198 toolkit/devtools/gcli/commands/media.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/devtools/gcli/commands/media.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,47 @@
+/* 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 gcli = require("gcli/index");
+
+exports.items = [
+  {
+    name: "media",
+    description: gcli.lookup("mediaDesc")
+  },
+  {
+    name: "media emulate",
+    description: gcli.lookup("mediaEmulateDesc"),
+    manual: gcli.lookup("mediaEmulateManual"),
+    params: [
+      {
+        name: "type",
+        description: gcli.lookup("mediaEmulateType"),
+        type: {
+           name: "selection",
+           data: [
+             "braille", "embossed", "handheld", "print", "projection",
+             "screen", "speech", "tty", "tv"
+           ]
+        }
+      }
+    ],
+    exec: function(args, context) {
+      let markupDocumentViewer = context.environment.chromeWindow
+                                        .gBrowser.markupDocumentViewer;
+      markupDocumentViewer.emulateMedium(args.type);
+    }
+  },
+  {
+    name: "media reset",
+    description: gcli.lookup("mediaResetDesc"),
+    manual: gcli.lookup("mediaEmulateManual"),
+    exec: function(args, context) {
+      let markupDocumentViewer = context.environment.chromeWindow
+                                        .gBrowser.markupDocumentViewer;
+      markupDocumentViewer.stopEmulatingMedium();
+    }
+  }
+];