Return accuracy in GPS emulation

Accuracy is now a required field for location. To comply, set an
accuracy in returned fix. The accuracy is constant for now since
computing it from the NMEA sentence seems to be very complicated.

Bug: 6864500

Change-Id: Iff4c36b440b095539c717d35a812ee2ed7c1725f

tools/emulator/system/gps/gps_qemu.c

@@ -405,6 +405,16 @@ nmea_reader_update_speed( NmeaReader*  r,
     return 0;
 }
 
+static int
+nmea_reader_update_accuracy( NmeaReader*  r )
+{
+    // Always return 20m accuracy.
+    // Possibly parse it from the NMEA sentence in the future.
+    r->fix.flags    |= GPS_LOCATION_HAS_ACCURACY;
+    r->fix.accuracy = 20;
+    return 0;
+}
+
 
 static void
 nmea_reader_parse( NmeaReader*  r )
@@ -488,6 +498,10 @@ nmea_reader_parse( NmeaReader*  r )
         tok.p -= 2;
         D("unknown sentence '%.*s", tok.end-tok.p, tok.p);
     }
+
+    // Always update accuracy
+    nmea_reader_update_accuracy( r );
+
     if (r->fix.flags != 0) {
 #if GPS_DEBUG
         char   temp[256];