[Runtime] Register system events information into database during installation.

As is mentioned in https://crosswalk-project.org/jira/browse/XWALK-519,
this PR registers system events at application install time. In detail,
after installation of application pacakge is completed, the main
document will be executed to register the events into system database.
Merge pull request #1235 from shaochangbin/register-system-events

[Runtime] Register system events information into database during installation.