Google Input Tools has recently been updated. They added Lisu (lis). Let me walk you through how you can add Chrome extension of Google Input Tools, and add Lisu keyboard (and Burmese if you like).
First, go to Google Chrome Web Store. Search for "Google Input Tools."
To add keyboards, click on the keyboard icon near the right corner of the browser's address bar as seen below. Choose the "Extension options."
You can now look for Lisu and add.
That's it. You can now type in Lisu or Burmese by choosing the right keyboard.
For Linux computer, I have written a post before.
For Windows 8 and above, the keyboard is built-in. You just need to activate it.
For Android, Multiling O Keyboard has Lisu. Newer version of Android (6.0) has Google's Noto Sans Lisu font pre-installed.
I don't know the situation on OSX and iOS.