Currently, application foreground/background notifications are listened for in WKContentView, and forwarded to WebPage via WebPageProxy. But because WebPage will just re-broadcast the notification within the WebContent process, this will lead to multiple notifications (and wasted work) being done if there are multiple Pages in the same WebContent process. This code should be moved to a singleton class (WebProcessPool would be a natural choice) and broadcasted only once per specific WebProcess instance.
<rdar://problem/77169224>