Merge "Return true if there were plugin sensors available" into qt-r1-dev

     * Requests for all sensors that match the given type from all plugins.

     * @param sensor

     * @param listener

     * @return true if there were plugins to register the listener to

     */

    public void registerPluginListener(SensorManagerPlugin.Sensor sensor,

    public boolean registerPluginListener(SensorManagerPlugin.Sensor sensor,

            SensorManagerPlugin.SensorEventListener listener) {

        if (mPlugins.isEmpty()) {

            Log.w(TAG, "No plugins registered");

            return false;

        }

        mHandler.post(() -> {

            for (int i = 0; i < mPlugins.size(); i++) {

                mPlugins.get(i).registerListener(sensor, listener);

            }

        });

        return true;

    }

    /**