On my asus transformer from about the same time era, chrome (and to a lesser extent firefox) spends much of its time writing to the slow emmc. I believe the N7 was also plagued by an extremely slow emmc with around 1-4 WIOPS performance?
This issue is something that has persisted with browsers for a longer time, across platforms. firefox was notoriously slow on Linux, due to the way it wrote cache and browsing history with sqlite. This issue is amplified further on flash based storage, where each tiny write triggers a 8 megabyte read-modify-write cycle. sqlite, being a database ish thing, is paranoid about dataloss, and makes sure the data is on physical storage after each step, with the end result that appending a new url to browser history, to a storage medium where every write request regardless whether it's 50 bytes or 8 megabytes takes on the order of 1 second to complete, you're looking at several seconds just to add to browsing history, let alone disk cache for images etc...
Ever since flash storage started appearing, programmers stopped caring about how they write stuff to disk, because "no moving parts, it's instant so I don't have to care". SSDs only started working like that, through the use of large Arm cores and massively complicated firmwares (that still today occasionally mess up), around the era of Intel M-25 and ocz vertex. Today if you're not careful, you'll get an emmc that still behaves as poorly as the one in N7.
Probably the only company that pays any attention to the issue is Motorola, with the use of f2fs, a filesystem which tries to make life easier for the emmc, boosting performance.