[Sensors] Align sensor reading attribute implementation with the specification

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

Index: third_party/WebKit/Source/modules/sensor/AmbientLightSensor.cpp
diff --git a/third_party/WebKit/Source/modules/sensor/AmbientLightSensor.cpp b/third_party/WebKit/Source/modules/sensor/AmbientLightSensor.cpp
index d124044da0da34ae8f0c2c8eaf7bbddf38d6fb9a..12af2edac73bf79b4e8300c54898c14106988bef 100644
--- a/third_party/WebKit/Source/modules/sensor/AmbientLightSensor.cpp
+++ b/third_party/WebKit/Source/modules/sensor/AmbientLightSensor.cpp
@@ -34,8 +34,10 @@ AmbientLightSensorReading* AmbientLightSensor::reading() const {
   return static_cast<AmbientLightSensorReading*>(Sensor::reading());
 }
 
-SensorReading* AmbientLightSensor::createSensorReading(SensorProxy* proxy) {
-  return AmbientLightSensorReading::create(proxy);
+std::unique_ptr<SensorReadingFactory>
+AmbientLightSensor::createSensorReadingFactory() {
+  return std::unique_ptr<SensorReadingFactory>(
+      new SensorReadingFactoryImpl<AmbientLightSensorReading>());
 }
 
 auto AmbientLightSensor::createSensorConfig(