I'd followed most of the advice I could find online, but ran across these extra steps to get the HAL working. It comes from a post on Amazon's Prime Instant Video support thread:

Stephen Gutknecht says:

On a new (virgin) install of Ubuntu 13.04 x64/x32 - there are some steps that I don't see getting enough attention.

In addition to:

close your Chromium/Chrome and Firefox:
sudo apt-get install libhal1 hal

***also do***

sudo mkdir /etc/hal/fdi/preprobe
sudo mkdir /etc/hal/fdi/information
/usr/sbin/hald --daemon=yes --verbose=yes
rm -rf ~/.adobe
rm -rf ~/.macromedia

Then open Chromium / Firefox fresh and give it a try!

This is what I did and have DRM FLash videos working smoothly in Chrome on Ubuntu using the Adobe Flash plugin with HAL installed.

I also asked here: https://productforums.google.com/forum/?utm_medium=email&utm_source=footer#!msg/chrome/QUPNuAndwAI/X9--o_OuBQAJ

JPApen suggested I install google-chrome-beta instead of google-chrome-stable and that fixed it - yay! They also said that google-chrome-stable would have this fixed in a couple weeks (today is 2016-02-14)

Details

I opened "Software & Updates" from the dash, picked the "Other Software" tab, clicked the Add button, and where it says "apt line" I put:

http://dl.google.com/linux/chrome/deb/ beta main

That's the same as the stable apt line except for the word beta.

Then from a command line:

sudo apt-get remove google-chrome-stable
sudo apt-get install google-chrome-beta

I actually used purge instead of remove because this is a relatively new installation and I didn't care about keeping my settings. Note that purge now removes your repository as well.

I did NOT need

• hal
• to be signed into chrome
• flashplugin-installer or any kind of flash (I think)