mash: Preliminary support for shelf auto-hide

ash/shelf/shelf_delegate.h

Index: ash/shelf/shelf_delegate.h
diff --git a/ash/shelf/shelf_delegate.h b/ash/shelf/shelf_delegate.h
index 16e041c4e454904b0b68dcd2282c408ac5513c33..17d861e8a38cd4be039c9a5669f693a1276e0f88 100644
--- a/ash/shelf/shelf_delegate.h
+++ b/ash/shelf/shelf_delegate.h
@@ -31,6 +31,12 @@ class ASH_EXPORT ShelfDelegate {
   // Called when |shelf|'s auto-hide behavior changes.
   virtual void OnShelfAutoHideBehaviorChanged(Shelf* shelf) = 0;
 
+  // Called after |shelf|'s auto-hide state changes.

[msw, 2016/05/25 01:10:33]

nit: s/after/when/ to be consistent. 'On*changed' somewhat indicates timing.

[James Cook, 2016/05/25 16:24:26]

Done, although frankly I would prefer all the comments to be specific about
before/during/after timing, because that would help readers learn our
OnFooChanging vs. OnFooChanged convention. But that's for another CL.

+  virtual void OnShelfAutoHideStateChanged(Shelf* shelf) = 0;
+
+  // Called when |shelf|'s visibility state is committed.
+  virtual void OnShelfVisibilityStateChanged(Shelf* shelf) = 0;
+
   // Get the shelf ID from an application ID.
   virtual ShelfID GetShelfIDForAppID(const std::string& app_id) = 0;