Remove Chrome shortcuts from app menu
Solution 1:
Remove it from Chrome.
Go to chrome://apps, right click the app you want to remove and select Remove from Chrome.
Those are Chrome desktop apps, not Ubuntu apps installed through Software Center or from deb package. That's why you can't remove them from Unity.
If it doesn't work, go to ~/.local/share/applications and look there for specific desktop files by ID. For example:
has the shortcut chrome-njkkjobcechefaoknodniidfjapgfoco-Default.desktop