[INTERNAL] moved content provider listeners

They listeners for requesting the content to update should appear in the
content provider class and not somewhere else.

Change-Id: I7f4a4ac685195db97ed52473ddb02f1c022eafd1
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1182
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>