Phone app to collect data from a Bluetooth OBD2 dongle via obd2_lib

Test: manual testing with a Vgate Scan and a Nexus 5X
Change-Id: I26d7f7e80b06eb067869ade2d7edb5e22c23731a
diff --git a/obd2-lib/src/com/android/car/obd2/Obd2Connection.java b/obd2-lib/src/com/android/car/obd2/Obd2Connection.java
index bfdb9c0..577b798 100644
--- a/obd2-lib/src/com/android/car/obd2/Obd2Connection.java
+++ b/obd2-lib/src/com/android/car/obd2/Obd2Connection.java
@@ -72,6 +72,10 @@
         return true;
     }
 
+    public boolean isConnected() {
+        return mConnection.isConnected();
+    }
+
     static int toDigitValue(char c) {
         if ((c >= '0') && (c <= '9')) return c - '0';
         switch (c) {