mash: Migrate some misc ShelfLayoutManager deps to ash common.

ash/aura/wm_shelf_aura.h

Index: ash/aura/wm_shelf_aura.h
diff --git a/ash/aura/wm_shelf_aura.h b/ash/aura/wm_shelf_aura.h
index 86d5186117ea806295fa1ca755e05909ef148c6f..76523ba1b4db2c56d7ce79f89db93f37ed1f6e36 100644
--- a/ash/aura/wm_shelf_aura.h
+++ b/ash/aura/wm_shelf_aura.h
@@ -15,6 +15,7 @@
 namespace ash {
 
 class Shelf;
+class ShelfBezelEventHandler;
 class ShelfLayoutManager;
 
 // Aura implementation of WmShelf.
@@ -87,6 +88,9 @@ class ASH_EXPORT WmShelfAura : public WmShelf,
   // Forwards mouse and gesture events to ShelfLayoutManager for auto-hide.
   std::unique_ptr<AutoHideEventHandler> auto_hide_event_handler_;
 
+  // Forwards touch gestures on a bezel sensor to the shelf.
+  std::unique_ptr<ShelfBezelEventHandler> bezel_event_handler_;

[James Cook, 2016/08/11 00:50:06]

Can you file a bug for coming up with a mus-compatible way to deal with bezel
events? It seems like something easy to forget. No need to reference the bug
here.

[msw, 2016/08/11 02:08:51]

Done; referenced it here anyway; similar above.

+
   DISALLOW_COPY_AND_ASSIGN(WmShelfAura);
 };