mash: Migrate ash_sysui wallpaper code to wm common types.
Migrating ash/desktop_background/* will be a mix of straightforward and more complex tasks.
desktop_background_controller.h WindowTreeHostManager::Observer -> WmDisplayObserver
desktop_background_controller.cc DisplayManager::GetDisplayInfo -> WmShell::GetDisplayInfo
desktop_background_controller.cc aura::Window -> WmWindow for
Shell::[user_wallpaper_delegate, desktop_background_controller] -> WmShell
Support WmRootWindowController::[OnWallpaperAnimationFinished, HandleInitialDesktopBackgroundAnimationStarted, animating_wallpaper_controller]
Support views::Widget::ReparentNativeView... (for locking, uses aura::Window)
Move ash/sysui/user_wallpaper_delegate_mus.* to ash/mus.
etc...
Comment 1 by bugdroid1@chromium.org
, Aug 2 2016