October 2020 - Code Health, Scroll Timelines, Synthetic User Activation, Scroll Unification and more!

<td><td>We made steady progress on bug fixes.</td></td>

<td><td>We held steady on P0s and P1s.</td></td>

<td><td>Nearly held steady on P2s, which is awesome!</td></td>

<td><td>Landed 13 patches.</td></td>

<td><td>Discovered two bugs.</td></td>

    <td><td><a
    href="https://bugs.chromium.org/p/chromium/issues/detail?id=1136516">Wrong
    error thrown</a>.</td></td>

    <td><td><a
    href="https://github.com/w3c/csswg-drafts/issues/5599">rootMargin
    missing in spec</a>.</td></td>

<td><td>215 new passing tests out of 354 total tests. The above graph shows
the number of passing tests when each patch landed.</td></td>

<td><td>Seeing expected results for non-extensions, but not expected for
extensions!</td></td>

<td><td>Ran finch experiment at 25% on Canary and Dev channels.</td></td>

<td><td>Expanded finch experiment to 50% Canary and Dev
(08-Oct-2020)</td></td>

<td><td>Currently in progress of moving to 50% on Canary, Dev and Beta
channels.</td></td>

<td><td>This makes ~10% of transform animations potentially less
janky.</td></td>

Code health

The graph shows our latest bug fixing efforts in this sprint:

Scroll timeline

flackr@ made tremendous progress on scroll timeline polyfill:

Synthetic user activation

TriggerForConsuming

TriggerForTrasient

TriggerForSticky

mustaq@ has done with UMA for synthetic triggers.

Scroll unification

liviutinta@ organized the remaining work on scroll unification, and splits the work between Q4 2020 and Q1 2021. This doc captures the work nicely.

Click/Auxclick as pointer event

mustaq@ is working on a finch experiment on this feature..

Composite transform animations containing percents

gtsteel@ has landed a complete implementation for animations targeting CSS boxes. The above demo shows the difference of running the animation on the main vs the compositor thread (with artificial jank).

Devtool input protocol

lanwei@ has merged the spec change of adding pointerevent’s additional properties to Webdriver Action API and added these properties to Devtool Input Protocol.