WHAT IS DOES?
==================
It is plug-in interface and default implement for CMCC case about duration of
capture quick review, items of scene mode, recording configuration.

HOW IT WAS BUILT?
==================
mmm vendor/mediatek/proprietary/packages/apps/Camera/ext

HOW TO USE IT?
==================
You can get an instance of ICameraFeatureExt interface by static method of
getCameraFeatureExtension in ExtensionHelper class. The instance will be the
object of DefaultCameraFeatureExt on not CMCC chip and will be plug-in
application which implement the ICameraFeatureExt interface on CMCC chip.

After get the instance of ICameraFeatureExt interface, you can invoke the API
to do the thing you want.