I'm running Gnome 3.10 on Ubuntu 14.04 LTS.

While I'm using battery the icon is there on the tray, when I plug AC not only battery icon is replaced with a power menu icon, battery information is also removed from the dropdown menu.

Issue is not related to hardware since I can use with Unity without any problems.

Here is some info:

xxVostro-5470:~$ gsettings get com.canonical.indicator.power show-time
true
xxVostro-5470:~$ gsettings get com.canonical.indicator.power show-percentage
true
xxVostro-5470:~$ gsettings get com.canonical.indicator.power icon-policy
'present'

It is also worth noting that when I am on battery, i.e. when I can see the battery indicator, if I change the settings of battery indicator via GUI, output of icon-policy is changed but battery icon remains on the tray.

Referring to another bug that was reported (https://bugzilla.gnome.org/show_bug.cgi?id=696122) here is the requested output:

xxVostro-5470:~$ gdbus introspect --session --dest org.gnome.SettingsDaemon.Power --object-path /org/gnome/SettingsDaemon/Power
node /org/gnome/SettingsDaemon/Power {
  interface org.freedesktop.DBus.Properties {
    methods:
      Get(in  s interface_name,
          in  s property_name,
          out v value);
      GetAll(in  s interface_name,
             out a{sv} properties);
      Set(in  s interface_name,
          in  s property_name,
          in  v value);
    signals:
      PropertiesChanged(s interface_name,
                        a{sv} changed_properties,
                        as invalidated_properties);
    properties:
  };
  interface org.freedesktop.DBus.Introspectable {
    methods:
      Introspect(out s xml_data);
    signals:
    properties:
  };
  interface org.freedesktop.DBus.Peer {
    methods:
      Ping();
      GetMachineId(out s machine_uuid);
    signals:
    properties:
  };
  interface org.gnome.SettingsDaemon.Power {
    methods:
      GetPrimaryDevice(out (susdut) device);
      GetDevices(out a(susdut) devices);
    signals:
    properties:
      readonly s Icon = '. GThemedIcon battery-low-charging-symbolic gpm-battery-020-charging battery-low-charging ';
      readonly s Tooltip = 'Laptop battery 1 hour 30 minutes until charged (28%)';
      readonly d Percentage = 28.0;
  };
  interface org.gnome.SettingsDaemon.Power.Screen {
    methods:
      StepUp(out u new_percentage);
      StepDown(out u new_percentage);
      GetPercentage(out u percentage);
      SetPercentage(in  u percentage,
                    out u new_percentage);
    signals:
      Changed();
    properties:
  };
  interface org.gnome.SettingsDaemon.Power.Keyboard {
    methods:
      StepUp(out u new_percentage);
      StepDown(out u new_percentage);
      Toggle(out u new_percentage);
    signals:
    properties:
  };
};

Best.