This moves normal/double/triple click checking into WebContent, the
client only has to send a click count in order to activate a double
or triple click in the content. This means that the AppKit UI will no
longer fire multiple double clicks when clicking in place more than 3
times. This matches the behavior of other browsers on macOS.
We will now also fire the click event regardless of whether a dblclick
event will follow, as the spec requires.
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