Add hasExternalControl hidden API to Vibrator

This capability will be queried by the AudioManager to be used to define
if the device has haptic playback capabilities.

Fix: 187227888
Test: N/A
Change-Id: Idc046d2fee12b3317db25975b29cf96f5f9c41b3

core/java/android/os/Vibrator.java

@@ -226,6 +226,17 @@ public abstract class Vibrator {
                 IVibrator.CAP_FREQUENCY_CONTROL | IVibrator.CAP_COMPOSE_PWLE_EFFECTS);
     }
 
+    /**
+     * Check whether the vibrator can be controlled by an external service with the
+     * {@link IExternalVibratorService}.
+     *
+     * @return True if the hardware can be controlled by an external service, otherwise false.
+     * @hide
+     */
+    public boolean hasExternalControl() {
+        return getInfo().hasCapability(IVibrator.CAP_EXTERNAL_CONTROL);
+    }
+
     /**
      * Gets the resonant frequency of the vibrator.
      *