postpone sending scroll mesage to webcore thread

post a message to the UI thread instead, to send the scroll message later

Change-Id: Iaf234effb77f1d8c6a50c9c288c5e8c269b38e40
Remove zombie content providers from ActivityManagerService

Change-Id: Iad5d01e5c62ffa6895d599c551c4055d24bf3c63