I'm reinstalling right now to test, it shows as a ~28MB download. I feel pretty confident it's not cached data in my case, as I don't use the Chrome browser on my phone (I prefer Dolphin with gestures & LastPass integration), and on a tablet I only use it for logging into wifi hotspots.
.... And after the reinstall it shows up as 65MB of app.
Checking.... Dolphin is a little weird on its own with the separate browser and "Dolphin Jetpack" (basically its own custom-built webkit engine).
Looking before removing Dolphin, Dolphin is showing 13.82MB of App plus 42MB of Data (which I believe could mostly be moved to phone storage). Also 2.3MB of cache.
Jetpack is showing 18.67MB of App, 4k of Data.
After reinstalling both and a first run of Dolphin (and restoring a slightly out of date backup for bookmarks, etc.), Dolphin is using 13.80MB of App and 4.66MB of Data, while Jetpack is using 18.67MB of App.
I'm not seeing the same thing happening with Dolphin as with Chrome.
.... And after the reinstall it shows up as 65MB of app.