Cinnamon: Power management applet does not tell user which program is inhibiting power management

[ghost]

```

• Cinnamon version (cinnamon --version) 3.6.7.
• Distribution - (Mint 17.2, Arch, Fedora 25, etc...) 18.2
• 32 or 64 bit: 64
  ```

Issue

The power management applet does not tell user which program is inhibiting power management. Thus, when I am confronted by this

I wonder whether it is the hung file transfers (see this nemo bug report) that are inihibiting the power-saving - or not.

Steps to reproduce

Hard to know - which, really, is the problem.

Expected behaviour

It would be good were the applet to give one a clue about the blocking program.

Other information

[clefebvre]

I suppose we could show the appId and reason in the tooltip. I think we've access to these via dbus.

[troxor]

This has been biting me lately, so here's _one_ way to determine this:

% dbus-send --session --print-reply --dest=org.gnome.SessionManager \
     /org/gnome/SessionManager \
     org.gnome.SessionManager.GetInhibitors
method return time=1520625795.516989 sender=:1.3 -> destination=:1.250 serial=2360 reply_serial=2
   array [
      object path "/org/gnome/SessionManager/Inhibitor79"
   ]

% dbus-send --session --print-reply --dest=org.gnome.SessionManager \
    /org/gnome/SessionManager/Inhibitor79 \
    org.gnome.SessionManager.Inhibitor.GetAppId
method return time=1520625994.042388 sender=:1.3 -> destination=:1.253 serial=2365 reply_serial=2
   string "/usr/bin/vivaldi-stable"



md5-6c4d25930a3973c0e452ca3148b575fd



% dbus-send --session --print-reply --dest=org.gnome.SessionManager \
    /org/gnome/SessionManager/Inhibitor79 \
    org.gnome.SessionManager.Inhibitor.GetReason
method return time=1520625799.584925 sender=:1.3 -> destination=:1.251 serial=2361 reply_serial=2
   string "WebRTC has active PeerConnections"

It turned out to be a pinned tab in the Vivaldi/Chrome browser inhibiting power management.