Revert 222512 "Group WM related properties to ash::wm::WindowSet..."
> Group WM related properties to ash::wm::WindowSettings
> * Introduced Observer to observe changes to the settings.
> * renamed UserHasChangedWindowPositinoOrSize to bounds_channed_by_user
>
> BUG=272460
>
> Review URL: https://chromiumcodereview.appspot.com/
23518006
REASON FOR REVERT:
- Causing compiler errors on the tree: Win Aura Builder
http://build.chromium.org/p/chromium.win/buildstatus?builder=Win%20Aura%20Builder&number=11959
TBR=oshima@chromium.org
Review URL: https://codereview.chromium.org/
23478025
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@222522 0039d316-1c4b-4281-b951-d872f2087c98