Thanks for reporting!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/527f565a588e4bd584d468071bf1ad5372dda9c4

commit 527f565a588e4bd584d468071bf1ad5372dda9c4
Author: Mikhail Pozdnyakov <mikhail.pozdnyakov@intel.com>
Date: Tue Nov 07 15:59:17 2017

[sensors] Fix simultaneous work of a fusion sensor and its sources

Before this change PlatformSensorFusion called the SensorStart and SensorStop
methods directly instead of calling them through StartListening/StopListening
which means that it could cause the source sensor clients to stop receiving
events.

Bug:  781378 
Change-Id: Idbcd4bded9f9de2831c9d9b8399f9b13165a545d
Reviewed-on: https://chromium-review.googlesource.com/754601
Reviewed-by: Alexander Shalamov <alexander.shalamov@intel.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Commit-Queue: Mikhail Pozdnyakov <mikhail.pozdnyakov@intel.com>
Cr-Commit-Position: refs/heads/master@{#514478}
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/fake_platform_sensor_and_provider.cc
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/fake_platform_sensor_and_provider.h
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/linear_acceleration_fusion_algorithm_using_accelerometer_unittest.cc
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/platform_sensor.cc
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/platform_sensor.h
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/platform_sensor_fusion.cc
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/platform_sensor_fusion.h
[modify] https://crrev.com/527f565a588e4bd584d468071bf1ad5372dda9c4/services/device/generic_sensor/platform_sensor_fusion_unittest.cc