Short-sighted. Chrome's original performance push didn't come at the expense of web platform features and that's part of why it was able to supplant existing browsers.
Any claims that this will improve performance in the long-term are misguided: These kinds of layout features are necessary, so stripping them from the core (especially when other browsers are implementing them) will result in a nasty mix of browser-specific pages and low-performance javascript shims.
> Chrome's original performance push didn't come at the expense of web platform features
What evidence is there that it did not come at the expense of Google support for any proposed Web Platform features that Google could not efficiently implement?
> The evidence is the feature-full browser that was Chrome
Which has good support for what were already web standards, and good support for what became web standards through, among other things, Google's support, but you haven't yet provided any evidence that, in choosing which proposed new standards to support, Google was at all reluctant to oppose any that would have conflicted with the optimization work it was doing.
(Given how bad the performance state of the web was, then, it may be the case that the proposed web standards at the time wouldn't have conflcited at all with the kinds of optimizations that were on the table -- which still doesn't show the claimed change in attitude vis-a-vis optimization and web standards, just as change in environment.)
You can get the same effect without java-script using Wrap and cutting an image into multiple sections. So, while useful long term there is little immediate need to add this feature if it's causing some issues.
Any claims that this will improve performance in the long-term are misguided: These kinds of layout features are necessary, so stripping them from the core (especially when other browsers are implementing them) will result in a nasty mix of browser-specific pages and low-performance javascript shims.