[sensors] Add Generic Sensor platform unit tests.

device/generic_sensor/platform_sensor_configuration.cc

Index: device/generic_sensor/platform_sensor_configuration.cc
diff --git a/device/generic_sensor/platform_sensor_configuration.cc b/device/generic_sensor/platform_sensor_configuration.cc
index 760d62eeaf32d3ecc789aa34f25ce658dd9c65e1..4d17dee23c1b70901f8d53ff9da345ebb2465008 100644
--- a/device/generic_sensor/platform_sensor_configuration.cc
+++ b/device/generic_sensor/platform_sensor_configuration.cc
@@ -19,4 +19,11 @@ bool PlatformSensorConfiguration::operator==(
   return frequency_ == other.frequency();
 }
 
+bool PlatformSensorConfiguration::operator>(
+    const PlatformSensorConfiguration& other) const {
+  // TODO(shalamov): Platform dependent configuration can override this
+  // operator when necessary.
+  return frequency() > other.frequency();
+}
+
 }  // namespace device