[build] Avoid to use non-existing file "evita/ui/compositor/layer_tree_owner.h".
[evita] views: Rename |EditPane::GetActiveWindow()| to |EditPane::GetActiveContent()|.
[evita] views: Introduce |views::TabContent::DidEnterSizeMove()| and |views::TabContent::DidExitSizeMove()| to resize tab content without animation during manual resizing.
[evita] views: Make tab drop to work.