[Sensors] OrientationSensor.quaternion returns [x, y, z, w]

third_party/WebKit/Source/modules/sensor/OrientationSensor.cpp

 // Copyright 2017 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.
 
 #include "modules/sensor/OrientationSensor.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/geometry/DOMMatrix.h"
 
 using device::mojom::blink::SensorType;
 
 namespace blink {
 
 Vector<double> OrientationSensor::quaternion(bool& is_null) {
   reading_dirty_ = false;
   is_null = !CanReturnReadings();
   return is_null ? Vector<double>()
-                 : Vector<double>({ReadingValueUnchecked(3),    // W
-                                   ReadingValueUnchecked(0),    // Vx
+                 : Vector<double>({ReadingValueUnchecked(0),    // Vx
                                    ReadingValueUnchecked(1),    // Vy
-                                   ReadingValueUnchecked(2)});  // Vz
+                                   ReadingValueUnchecked(2),    // Vz
+                                   ReadingValueUnchecked(3)});  // W
 }
 
 template <typename T>
 void DoPopulateMatrix(T* target_matrix,
                       double x,
                       double y,
                       double z,
                       double w) {
   auto out = target_matrix->Data();
   out[0] = 1.0 - 2 * (y * y + z * z);
@@ skipping 97 matching lines @@
 
 void OrientationSensor::OnSensorReadingChanged() {
   reading_dirty_ = true;
 }
 
 DEFINE_TRACE(OrientationSensor) {
   Sensor::Trace(visitor);
 }
 
 }  // namespace blink