Exposing Context Hub service.

Adding the Context hub service. This is the service that exposes
the context hub HAL to the system. The API exposed is a System API.

Change-Id: I854141714ecd21f6386e6b15b7bc9a997483ccf6

services/java/com/android/server/SystemServer.java

@@ -1020,6 +1020,7 @@ public final class SystemServer {
                     mSystemServiceManager.startService(GestureLauncherService.class);
                 }
                 mSystemServiceManager.startService(SensorNotificationService.class);
+                mSystemServiceManager.startService(ContextHubSystemService.class);
             }
 
             traceBeginAndSlog("StartDiskStatsService");