Google owns Android, which is obvious. But how the two look so different, Chrome and Android that is, is simply due to the effort not being there, the effort to unify experiences across platforms and form factors. Microsoft was the first to take steps toward experience unity with the release of Windows 8 and the Metro UI, which matched the Xbox's menu system and aligned itself with the tiled interface on Windows Phone OS, creating an obviously united and similar experience across any device or platform. Apple was the second to do this, with the effort being more in what you can do on each device, most of which was unveiled at WWDC 2014 a few weeks ago. Apple moves were functionality across all Mac applications, like being able to send a text through iMessage on your Macbook then pick up your phone and go to class and continue the same conversation and thread seamlessly.
Google is the last of the big three to make its way in the direction of unity, but it isn't a shoddy or 'because we have to'-looking effort in the least. Android, being Google's favorite child along with Chrome, is being worked on and reworked from the ground up for the latest release which is currently named Android L, and Google is taking the chance to redesign the interface and experience on Chrome to line up better with Android. Google's move has a name too, and that name is Material Design.
Material, for short, is a look where items on the screen have depth and are in a three-dimensional plane, instead of just a flat thing where they overlap. Google is redesigning Android to have this depth, and floating interface aspects, and Chrome will likely be the next target after Android L rolls out this fall. The new interface features a colored experience, and revamped menus and multitasking, with the latter looking like the tab management within the Chrome app. What's also similar between Android and Chrome is the coming ability to have a developer build in code so that the Android app can be installed on a Chromebook, and have it run that Android app but on the laptop.
Google is also extending the reach and compatibility of Android, adding watches and televisions as well as cars, so that your phone is essentially the hub for all things you use. With the inbuilt design language of Material, the experience will just resize, reorient, and adjust a few minor things to create a connected single interface and experience. Google is linking into everything that Android is and is based on, and using the tapped-into power to link your world, and all this starts with your phone.