According to Google, "every touch-based mobile browser, across platforms, has an artificial ~300ms delay between you tapping a thing on the screen and the browser considering it a click". Google has managed to remove this huge 300ms delay for mobile-optimized websites in the beta version of Chrome for Android, version 32, but this improvement will of course arrive for the stable version, too, about 6 weeks from now.
This improvement shouldn't affect pinch to zoom, according to Google developer Jake Archibald, but you won't be able to double tap to zoom on some pages. This is a little disappointing to me, because I actually prefer double tapping and I almost never use pinch to zoom in the browser, because double tapping gave me exactly what I wanted, quickly and without too much effort at all. But the removal of this 300ms touch lag seems well worth it, so I'm willing to live without the double tap to zoom functionality.
Apparently this change isn't completely new, as both Firefox and Chrome have already disabled that delay on websites that didn't support zooming. So this delay was caused only by mobile websites that supported double tap zooming, presumably because the website needed time to process whether your normal "tap" was a single one, or half of a double tap. If the delay was much smaller for double tapping, it wouldn't have worked before. But now they are just getting rid of it to cut the delay, and improve the overall experience.
Mozilla still hasn't fixed this in Firefox Mobile for mobile websites, but it has an open ticket that asks for a fix in Firefox Mobile. Presumably, they will fix it soon, too. You can watch in the video below a demonstration for how the mobile websites worked before, with the 300ms lag, and how they work now without that touch lag.
Google has begun working on a lot of things latest that are meant to improve touch response, animation fluidity and eliminate lag from the OS and apps, and I hope they keep this up, because they may seem small issues, but they can quickly add-up and create an overall poorer experience for the user if everything is not working flawlessly.