[Sensors] Remove SensorReading interfaces

third_party/WebKit/Source/modules/sensor/Accelerometer.idl

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Specification at:
 // https://w3c.github.io/accelerometer/#accelerometer-interface
 
 [
     RuntimeEnabled=Sensor,
     Constructor(optional AccelerometerOptions sensorOptions),
     ConstructorCallWith=ExecutionContext,
     RaisesException=Constructor,
 ] interface Accelerometer : Sensor {
-    readonly attribute AccelerometerReading? reading;
+    readonly attribute unrestricted double? x;
+    readonly attribute unrestricted double? y;
+    readonly attribute unrestricted double? z;
     readonly attribute boolean includesGravity;
 };