healthd: charger: Add tricolor led to indicate battery capacity

Add led to indicate battery capacity when doing off mode charging. The
led behavior is design as below:
   i. 	Shows red led if capacity is lower than 15%.
   ii.	Shows yellow (red + green) led if capacity is
	lower than 90% but higher than 15%.
   iii. Shows green led if capacity is higher than 90%.

Change-Id: If637defec8a04e859b00a6492ec1f95d6bff2200
healthd: charger: Turn off charging animation by power key event

Currently, the charging animation can be turned on by power key event. Add
support to make charging animation can be turned off by power key event.

Change-Id: Icc8101ae3d4fd777efedeff10ca535a9e6e7a57d
healthd: charger: Draw battery capacity in charging animation

Draw a text to show the battery capacity value in charging animation.

Change-Id: I0117fb0aee69181ce0d608ba4b1644fa42cd1a0d
healthd: charger: Modify charger unplug shutdown time to 1s

Modify UNPLUGGED_SHUTDOWN_TIME from 10 seconds to 1 second to make sure
device can shutdown quickly after charger is plugged out.

Change-Id: I73f149295ca73756a210e7cb3dd61f955aa18165
healthd: charger: Support alarm in power off charging mode

To implement this feature need to let the phone reboot some time
earlier than the alarm time.

CRs-fixed: 727939
Change-Id: I67832ec089eddd436a4daee7c6808ab2eaa69213
healthd: charger: Add backlight control in charging animation

On some targets the FBIOBLANK does not control the backlight. Add the
backlight control in charging animation to make sure the backlight will
be turned on/off successfully.

Change-Id: I3bba3b58daba6cffa4eb1314a6da1542f43e8e47
charger: check the charging_enabled at the beginning of power off charging

Check charging_enabled flag in power off charging process, reboot the
device if charging is disabled to exit power off charging mode.

Change-Id: I11208acb1dd82a06b42911fdbcc7e58f6f97e96c