As it says in the summary.
Created attachment 196297 [details]
I have a follow-up patch that I'll post after this one is landed which cleans up registerOcclusionNotificationHandlers / unregisterOcclusionNotificationHandlers.
Attachment 196297 [details] did not pass style-queue:
Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/WebKit2/ChangeLog', u'Source/WebKit2/UIProcess/mac/WebContextMac.mm']" exit_code: 1
Source/WebKit2/ChangeLog:1: ChangeLog entry has no bug number [changelog/bugnumber] 
Total errors found: 1 in 2 files
If any of these errors are false positives, please file a bug against check-webkit-style.
Comment on attachment 196297 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=196297&action=review
> + <rdar://problem/13540351> Enable process suppression when no windows in the application have drawn recently.
Please add the bugs.webkit.org bug number.
> + (WebKit):
Please remove bogus lines like this.
This was landed back in r147592.