Allow an EventTarget to provide the default value of the AddEventListenerOptions


Continuing our work with Google HTML/DOM Interop


We submitted a spec PR to specify default passive for document-level wheel/mousewheel/touchstart/touchmove events as implemented in Chromium, WebKit and Gecko (except for mousewheel in Gecko because that event is not implemented), and corresponding wpt tests.


We also identified that the hack for smoothscroll.js was dead code in both Chromium and WebKit; it was only effective before they implemented default passive events.

We further wrote related tests to verify that events are not cancelable when there are no non-passive event listeners, and cancelable when there are non-passive event listeners. We filed an issue about the specification not being sufficiently clear about the expected behavior.

The mousewheel event is not specified and not implemented in Gecko, but supported in Chromium and WebKit. We filed a spec issue about this lack of interoperability.


The specification now defines how default passive events should work and there is test coverage in web-platform-tests, which helps new implementations and avoids regressions for current implementations.

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