Comment 2 for bug 1509044

Two issues here:

1. The intel kernel driver does/did on rare occasions lose vsync. That's a kernel issue which will go away on reboot. But also probably not the main problem.

2. Fullscreen windows in Unity7/Compiz get "unredirected" for performance so they are not composited by Compiz any more. This means they will tear unless "unredirection" is explicitly disabled for them:

    $ sudo apt-get install compizconfig-settings-manager
    $ ccsm
   General > Composite > General >

Now either add a match for Chromium into "Unredirect Match" (if you can figure out how), or to simply disable the feature for all apps untick "Unredirect Fullscreen Windows". Tearing eliminated.

Also check the default settings for avoiding tearing are in place in CCSM:
   General > OpenGL > General > Always use buffer swapping = ON (means it won't tear)