On Chrome Version 30.0.1599.69 on Mac OSX 10.8.5 the Command+Delete keyboard shortcut is ignored. In most text editors it deletes the entire line of content (try it in gmail or on bugzilla!)

The Option+Delete keyboard key (to delete the previous word) and Option+Fn+Delete (to delete the following word) do work correctly. There is no Command+Fn+Delete shortcut.

I do not have easy access to test this shortcut on other versions of Chrome, nor do I know what the shortcut is on Firefox.