[gnome-shell] (8 commits) Non-fast-forward update to branch wip/fmuellner/window-close

[Florian Müllner <fmuellner src gnome org>]

The branch 'wip/fmuellner/window-close' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  d450649... theme: Drop custom assets for window close buttons in overv
  2443b22... theme: update css for window close button

Commits added to the branch:

  04d7069... app-usage: Remove crufty old "context"s idea (*)
  c3ec813... app-usage: Remove unused open-window-count attribute (*)
  43041f0... app-usage: Remove more unused things (*)
  74bb9e6... ibusManager: Don't pass undefined callback to ibus (*)
  e77463b... altSwitcher: Fix error when all alternatives are disabled (*)
  ff2fbf5... dash: destroy items's child before tooltip (*)
  8e7c90b... theme: Replace corner ripple png assets with css (*)
  855c0dc... theme: Drop custom assets for window close buttons in overv

(*) This commit already existed in another branch; no separate mail sent