Enhance bootstat_summary to accept a list of events.

If provided with arguments, the script will summarize only the named
events.  If no arguments are provided, the script summarizes all
available events, just as before.

BUG=None
TEST=run the command with and without arguments

Change-Id: I21fdcced548d5a1d63c62b8e40f3817342319c46
Reviewed-on: https://gerrit.chromium.org/gerrit/48821
Reviewed-by: Daniel Erat <[email protected]>
Commit-Queue: Richard Barnette <[email protected]>
Tested-by: Richard Barnette <[email protected]>
Reviewed-by: Sonny Rao <[email protected]>
1 file changed