One question I have in mind: Will Safari be able to keep up, or will Apple become complacent because they're satisfied with being the best option for OS X? (Which they can achieve by being insiders on that OS, and not by being more awesome.)
Very rarely is Safari the first to adopt anything, because frankly they almost never are the ones working on drafts. I firmly believe Apple sees the web as "that thing we have to have but don't want to devote too many resources to."
I find myself using less and less my iPad (last generation with A7) for a single reason: because how much web sites are actually cluttered with pop-ups, ad banners, and modal sheets masking contents. This has a serious impact on loading times and on usability, this is maddening.
This is becoming a serious problem aggravated by the fact developers of these websites / ad networks know very well there is actually no mainstream way of bypassing this garbage on iOS and thus they abuse their situation. Apple needs to do something to restore a balance. I won't hold my breadth though, but long term as it drives more people nuts I think it will become a serious issue.
If so, "best" option for OSX seems somewhat moot: what really counts is being the "only" option on iOS. (Technically, you can install another Webkit-based powered browser on an iDevice, but I'd wager hardly anyone does so because http links in apps would probably keep opening Safari anyway.)
Links from other (non-Google) apps still open in Safari.
I had intended the trivia about gmail:chrome integration as a way to illustrate the parent's opinion that Apple controlling the user experience on the iPad is, ultimately, a moot point.
If Apple cannot prevent the distribution third party browsers (note: see caveat in comment above), and they cannot prevent other apps from invoking those third party browsers, then Apple cannot prevent a company with sufficient drive and resources from creating a self-reinforcing ecosystem on top of iOS. All they can do is raise the barrier to entry, to increase the likelihood that smaller players will build on top of the iOS ecosystem, rather than do an end-run around it.
Just in case there is any ambiguity, I am glad that Google is innovating (to the extent that they are permitted) on top of iOS. I tend to buy Apple gear because I think that Apple makes very good hardware, and I use OS X because it's a desktop-centric Unix that runs software from Adobe and Microsoft, and lets me watch videos from Netflix and Amazon.
As someone who has used Apple services since iTools debuted in 2000, I think that Apple's services (iCloud, iTunes, etc) are strictly "ehh." I'm glad to see the competition. If Safari usage numbers tank as a result, well, that's a solvable problem.
It's also worth pointing out that Chrome on your iPad is just Mobile Safari (the slower version for 3rd party apps) with a Chrome skin/UI on top of it. It's not the real Chrome/Blink engine used on Mac, Windows, Linux, Android, etc, which would be faster.