TL;DR: I would like to have the same thing as described here, but for Elementary OS.
I want to have the (graphical) terminal and Emacs windows the header or without any decorations. Does anyone know how to do this?
Off topic, but indirectly related: I see a little to no use of the border and the headers of the windows. Fortunately, elementary OS puts acceptable borders on the windows, but the header is still a disaster. The header info could appear on mouse-over or in the common header line like it is done in OSX.
If there is any movement in this or similar direction, please let me know.
P.S. Emacs works not inside the terminal.
P.P.S. I see that this question is a little bit related, but I cannot figure out how to reach the expected result.
UPDATE: This is in fact a final answer on initial question, but I don't want to add another one as Daniel Foré has already provided the acceptable answer.
I changed the source code so that decorations and scrollbar are disabled (thanks Daniel!), but the problem is a bit deeper: it is necessary to do something with tabs, but it seems the terminal simply needs another, "naked" mode which would disable everything plus setting the terminal into the single window mode (no invisible tabs).
For those who are interested, it was only
set_decorated(false); in function
init, about line 123 in file PantheonTerminalWindow.vala and also I disabled the scrollbar commenting out the line
g.attach (sb, 1, 0, 1, 1) (line number about 579). The hack is dirty, but it was good enough to see that disabling the decorations is just not enough. Alas.