fix healthd charger mode.

Healthd has an optional "charger" mode. The device boots into a
minimally running mode, and healthd displays the battery indicator.

Without this patch, when a manta device boots into charger mode,
the screen will never turn off and the battery indicator will not move.

From reviewing the healthd code, it looks like this may affect lots
of devices, not just manta. I'm adding this change to the generic
policy.

Steps to reproduce:

1) Make sure the device is unplugged.
2) Boot into a normal system.
3) Shutdown the system normally using the power button.
4) After shutdown, plugin the power cord.
5) Device will boot into charger mode. Battery icon will display.
6) Press the button to reboot into a normal mode.
7) Examine /proc/last_kmsg and look for denials.

Addresses the following denials:

[    3.908457] type=1400 audit(1390866386.620:3): avc:  denied  { read write } for  pid=98 comm="charger" name="fb0" dev="tmpfs" ino=4286 scontext=u:r:healthd:s0 tcontext=u:object_r:graphics_device:s0 tclass=chr_file
[    3.909085] type=1400 audit(1390866386.620:4): avc:  denied  { open } for  pid=98 comm="charger" name="fb0" dev="tmpfs" ino=4286 scontext=u:r:healthd:s0 tcontext=u:object_r:graphics_device:s0 tclass=chr_file
[    3.909749] type=1400 audit(1390866386.620:5): avc:  denied  { ioctl } for  pid=98 comm="charger" path="/dev/graphics/fb0" dev="tmpfs" ino=4286 scontext=u:r:healthd:s0 tcontext=u:object_r:graphics_device:s0 tclass=chr_file
[    4.889857] type=1400 audit(1390866387.605:6): avc:  denied  { read } for  pid=98 comm="charger" name="input" dev="tmpfs" ino=4153 scontext=u:r:healthd:s0 tcontext=u:object_r:input_device:s0 tclass=dir
[    4.890873] type=1400 audit(1390866387.605:7): avc:  denied  { open } for  pid=98 comm="charger" name="input" dev="tmpfs" ino=4153 scontext=u:r:healthd:s0 tcontext=u:object_r:input_device:s0 tclass=dir
[    4.891949] type=1400 audit(1390866387.605:8): avc:  denied  { search } for  pid=98 comm="charger" name="input" dev="tmpfs" ino=4153 scontext=u:r:healthd:s0 tcontext=u:object_r:input_device:s0 tclass=dir
[    4.892677] type=1400 audit(1390866387.605:9): avc:  denied  { read } for  pid=98 comm="charger" name="event2" dev="tmpfs" ino=4279 scontext=u:r:healthd:s0 tcontext=u:object_r:input_device:s0 tclass=chr_file
[    4.893576] type=1400 audit(1390866387.605:10): avc:  denied  { open } for  pid=98 comm="charger" name="event2" dev="tmpfs" ino=4279 scontext=u:r:healthd:s0 tcontext=u:object_r:input_device:s0 tclass=chr_file
[    7.288104] type=1400 audit(1390866389.999:12): avc:  denied  { execmem } for  pid=98 comm="charger" scontext=u:r:healthd:s0 tcontext=u:r:healthd:s0 tclass=process
[    7.288574] type=1400 audit(1390866389.999:13): avc:  denied  { execute } for  pid=98 comm="charger" path="/dev/ashmem" dev="tmpfs" ino=4113 scontext=u:r:healthd:s0 tcontext=u:object_r:ashmem_device:s0 tclass=chr_file

Change-Id: I0118e08514caa0ad11d2aa7562c9846a96779a21

healthd.te

@@ -14,3 +14,14 @@ allow healthd self:netlink_kobject_uevent_socket create_socket_perms;
 binder_use(healthd)
 binder_service(healthd)
 binder_call(healthd, system_server)
+
+###
+### healthd: charger mode
+###
+
+allow healthd graphics_device:dir r_dir_perms;
+allow healthd graphics_device:chr_file rw_file_perms;
+allow healthd input_device:dir r_dir_perms;
+allow healthd input_device:chr_file r_file_perms;
+allow healthd ashmem_device:chr_file execute;
+allow healthd self:process execmem;