Libreoffice 3.4 was installed in /opt and a link to the executable was put in /usr/bin, but Unity search can't find it. Also, if I open Libreoffice Writer, for instance, and ask to keep its icon in launcher, it doesn't work afterwards.
You can try creating a laucher icon. Do the following:
Right-click on your desktop and select Create Laucher option:
A dialog box is going to prompt. You may now set up your laucher.
By clicking on the Browse button you may select the file to be executed. (in this case, google chrome)
Having everything set, click OK and a new laucher will be added to your desktop folder.
Now, you may cut and paste it wherever you want, as well as drag and drop it to your Unity bar (whateverthenameofthiscrapis).