Google replaced it with a gesture that's less error-prone: "swipe horizontally across the top toolbar to quickly switch tabs". It's hard to this accidentally when browsing the web. Google added other gestures: "Drag vertically down from the toolbar to enter into the tab switcher view. And drag down from the menu to open the menu and select the item you want without having to lift your finger. Zoom into your preferred magnification on any desktop web site by double tapping on the page and swiping your finger up-down without lifting it."
Chrome 30 for Android brings a lot of other useful features: WebGL support, media source extensions for adaptive streaming and time shifting live streams, DeviceMotion events and reverse image search powered by Google.
Reverse image search (or search by image) is also natively supported in Chrome 30 for desktop: just right-click an image and pick "search Google for this image".
Chrome Beta for Android is available in Google Play, while Chrome Beta for desktop can be downloaded from here.