Decrease size of Event object by 8 bytes.
Decrease size of Event object by 8 bytes.

This change decreases the size of the Event object from
112 to 104 by using a bit set. I need to add another boolean
and realized this object wasn't packed sufficiently.

BUG=334015

Review URL: https://codereview.chromium.org/1222623004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@198235 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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