Ignore clicks on iframes that have moved in the last 200 ms

[alijuma]

Unintended clicks on recently-moved elements are a frustrating but common problem.

To address this, Chrome is considering ignoring clicks on cross-origin iframes when the location of the click would not have been within the bounds of the iframe for all draws that happened within the last 200 ms.

More background can be found here.

[szager-chromium]

I would like to revive this proposal, with a few tweaks explained in this updated doc

[johannhof]

(As noted in #72, we intend to archive this repository and are thus triaging and resolving all open issues)

Following up in whatwg/html#8012