Auto merge of #14597 - gterzian:fix_scroll_transactions, r=mbrubeck
Auto merge of #14597 - gterzian:fix_scroll_transactions, r=mbrubeck

FIX for Implement scroll transactions

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Follow up on https://github.com/servo/servo/pull/14470

@mbrubeck @KiChjang @glennw I just found out in the context of https://github.com/servo/webrender/pull/600 I forgot to add a case for the very first scroll event, or else the scrolling on that PR, in a non-Mac OS environment, will only start after an 80ms pause following the initial scroll event...

Sorry this slipped through my initial testing...

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