Whenever Blimp tabs are loaded, there is no visual indicator that this tab is a Blimp tab. There is also no visual indicator as to whether a new tab will be a blimp tab or not.

Some visual indicator should be added to ensure that it is possible for users to identify the (currently only) tab holding a BlimpContents.

The simplest fix would probably be to just use a specific theme color for blimp tabs. You can look here:
https://chromium.googlesource.com/chromium/src/+/e942099e4a004adb1a7720282327bcabd8f27d72/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java#1097

We probably want to still be able to run the security-related code, etc., so following what we do for WebContents and do something similar would probably be good. We would ask the BlimpContents for the theme color so that we can ensure that when we later pipe the data through from the engine, we will use the theme color from the site.