As noted by TheNextWeb, Google released a new update for Gmail for iOS today, adding the ability to open links from the app in Chrome for iOS (as Google has been doing with all of their apps lately).
While users can’t officially set Google Chrome as their default browser in iOS (or any other 3rd-party browser), those who heavily use Google’s apps can achieve a similar effect now that Google has altered their apps with the feature.
The update doesn’t appear to have made any significant changes other than the ability to open links in Chrome for iOS. Both apps are available for free through the App Store.
Does not work for gmail app v2 on iOS 6