WebKit needs the ability to dispatch mouse wheel events from JavaScript in order to test WebKit scrolling behavior programatically. For instance, https://bugs.webkit.org/show_bug.cgi?id=29601 cannot be properly tested without such a capability.
<rdar://problem/7705815>
Created attachment 49790 [details] Proposed patch
Comment on attachment 49790 [details] Proposed patch Suggestions from IRC: - instead of the long comments explaining the difference between m_wheelDeltaX/Y and m_deltaX/Y, I would suggest giving them names that make the difference more clear - m_wheelDeltaX/Y are exposed by that name in the API, perhaps the others could be m_rawDeltaX/Y or m_pixelDeltaX/Y r=me with that change.
Created attachment 49793 [details] Proposed patch (v2) Updated the patch to address Maciej's comments.
Comment on attachment 49793 [details] Proposed patch (v2) r=me
Landed in r55436 since the commit queue seems uninterested in committing changes.