We're getting close! The latest upgrade installs Chromium v67, which should be capable of running Amazon, but it doesn't. It starts Amazon Prime, and looks like it will start a video then throws a "update required" message.
I used the original package from the OP, but commented out the chromium v63 dpkg install in install.sh. With the widevine and pepper install, it will run Netflix.
I got even farther with Amazon just now. I believe it is the /usr/share/applications/chromium-user.desktop file. It is apparently this line:
Code:
Exec=/usr/bin/chromium --user-agent="Mozilla/5.0 (X11; CrOS armv7l 6946.63.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/45.0.2357.130 Safari/537.36" %U
I changed it to Chrome/67.0.3396.87, and it starts without throwing the "update required" message, but can't start the video. It pops up a box with "video unavailable" and a link to a page that says something about the Chrome web player.
Edit: I got it to work with both Netflix and Amazon. I don't have Hulu. Install the original package from the OP (with the Chrome dpkg) per the directions.
Open /usr/share/applications/chromium-user.desktop with a text editor.
Locate the Exec= line like above and change
Chrome/45.0.2357.130
to
Chrome/67.0.3396.87
Reboot.
Select the Internet -> Chromium web browser (user)