diff -r 000000000000 -r 6474c204b198 widget/windows/winrt/WakeLockListener.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/widget/windows/winrt/WakeLockListener.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,29 @@
+/* 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 "WakeLockListener.h"
+#include "MetroUtils.h"
+
+using namespace mozilla::widget::winrt;
+
+NS_IMPL_ISUPPORTS(WakeLockListener, nsIDOMMozWakeLockListener)
+
+NS_IMETHODIMP
+WakeLockListener::Callback(const nsAString& aTopic, const nsAString& aState)
+{
+  if (!mDisplayRequest) {
+    if (FAILED(ActivateGenericInstance(RuntimeClass_Windows_System_Display_DisplayRequest, mDisplayRequest))) {
+      NS_WARNING("Failed to instantiate IDisplayRequest, wakelocks will be broken!");
+      return NS_OK;
+    }
+  }
+
+  if (aState.Equals(NS_LITERAL_STRING("locked-foreground"))) {
+    mDisplayRequest->RequestActive();
+  } else {
+    mDisplayRequest->RequestRelease();
+  }
+
+  return NS_OK;
+}