Add Looper to the threat that plugin runs in.
Add Looper to the threat that plugin runs in.

This fixes the issue that Geolocation plugin does not work.
In XWalk, the thread which ExposedJsApi.exec() runs in does not contain
a message loop. As android.location.LocationManager need a loop to
process message, we have to prepare a Looper manually.

hgl888/crosswalk-cordova-android,awesome-niu/crosswalk-cordova-android,crosswalk-project/crosswalk-cordova-android,rakuco/crosswalk-cordova-android,rakuco/crosswalk-cordova-android,chengxiaole/crosswalk-cordova-android,chengxiaole/crosswalk-cordova-android,hgl888/crosswalk-cordova-android,rakuco/crosswalk-cordova-android,awesome-niu/crosswalk-cordova-android,crosswalk-project/crosswalk-cordova-android,chengxiaole/crosswalk-cordova-android,crosswalk-project/crosswalk-cordova-android,awesome-niu/crosswalk-cordova-android,hgl888/crosswalk-cordova-android