Update AccelerometerReader to support separate iio devices

content/browser/device_sensors/sensor_manager_chromeos.cc

 // Copyright 2015 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 "content/browser/device_sensors/sensor_manager_chromeos.h"
 
 #include <math.h>
 
 #include "chromeos/accelerometer/accelerometer_reader.h"
 #include "chromeos/accelerometer/accelerometer_types.h"
@@ skipping 122 matching lines @@
   motion_buffer_->seqlock.WriteEnd();
 }
 
 void SensorManagerChromeOS::GenerateOrientationEvent(double x,
                                                      double y,
                                                      double z) {
   if (!orientation_buffer_)
     return;
 
   // Create a unit vector for trigonometry
-  // TODO(jonross): Stop reversing signs for vector components once
-  // accelerometer values have been fixed. crbug.com/431391
-  // Ternaries are to remove -0.0f which gives incorrect trigonometrical
-  // results.
-  gfx::Vector3dF data(x, y ? -y : 0.0f, z ? -z : 0.0f);
+  gfx::Vector3dF data(x, y, z);
   data.Scale(1.0f / data.Length());
 
   // Transform accelerometer to W3C angles, using the Z-X-Y Eulerangles matrix.
   // x = sin(gamma)
   // y = -cos(gamma) * sin(beta)
   // z = cos(beta) * cos(gamma)
   // With only accelerometer alpha cannot be provided.
   double beta = kRad2deg * atan2(data.y(), data.z());
-  double gamma = kRad2deg * asin(data.x());
+  double gamma = kRad2deg * asin(-data.x());
 
   // Convert beta and gamma to fit the intervals in the specification. Beta is
   // [-180, 180) and gamma is [-90, 90).
   if (beta >= 180.0f)
     beta = -180.0f;
   if (gamma >= 90.0f)
     gamma = -90.0f;
   orientation_buffer_->seqlock.WriteBegin();
   orientation_buffer_->data.beta = beta;
   orientation_buffer_->data.hasBeta = true;
   orientation_buffer_->data.gamma = gamma;
   orientation_buffer_->data.hasGamma = true;
   orientation_buffer_->data.allAvailableSensorsAreActive = true;
   orientation_buffer_->seqlock.WriteEnd();
 }
 
 }  // namespace content