diff -r 000000000000 -r 6474c204b198 xpcom/system/nsIDeviceSensors.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/system/nsIDeviceSensors.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,51 @@
+/* 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 "nsISupports.idl"
+
+interface nsIDOMWindow;
+
+[scriptable, uuid(1B406E32-CF42-471E-A470-6FD600BF4C7B)]
+interface nsIDeviceSensorData : nsISupports
+{
+  // Keep in sync with hal/HalSensor.h
+  const unsigned long TYPE_ORIENTATION = 0;
+  const unsigned long TYPE_ACCELERATION = 1;
+  const unsigned long TYPE_PROXIMITY = 2;
+  const unsigned long TYPE_LINEAR_ACCELERATION = 3;
+  const unsigned long TYPE_GYROSCOPE = 4;
+  const unsigned long TYPE_LIGHT = 5;
+
+  readonly attribute unsigned long type;
+
+  readonly attribute double x;
+  readonly attribute double y;
+  readonly attribute double z;
+};
+
+[scriptable, uuid(e46e47c7-55ff-44c4-abce-21b14ba07f86)]
+interface nsIDeviceSensors : nsISupports
+{
+  /**
+   * Returns true if the given window has any listeners of the given type
+   */
+  bool hasWindowListener(in unsigned long aType, in nsIDOMWindow aWindow);
+
+  // Holds pointers, not AddRef objects -- it is up to the caller
+  // to call RemoveWindowListener before the window is deleted.
+
+  [noscript] void addWindowListener(in unsigned long aType, in nsIDOMWindow aWindow);
+  [noscript] void removeWindowListener(in unsigned long aType, in nsIDOMWindow aWindow);
+  [noscript] void removeWindowAsListener(in nsIDOMWindow aWindow);
+};
+
+%{C++
+
+#define NS_DEVICE_SENSORS_CID \
+{ 0xecba5203, 0x77da, 0x465a, \
+{ 0x86, 0x5e, 0x78, 0xb7, 0xaf, 0x10, 0xd8, 0xf7 } }
+
+#define NS_DEVICE_SENSORS_CONTRACTID "@mozilla.org/devicesensors;1"
+
+%}