mash: Preliminary support for shelf auto-hide

ash/mus/shelf_delegate_mus.h

Index: ash/mus/shelf_delegate_mus.h
diff --git a/ash/mus/shelf_delegate_mus.h b/ash/mus/shelf_delegate_mus.h
index 5baba1b38147dc32f5b83054ad86d998a1f9a17a..e6e59f761fc650dc1fa16922a2124a50b9620ae6 100644
--- a/ash/mus/shelf_delegate_mus.h
+++ b/ash/mus/shelf_delegate_mus.h
@@ -8,6 +8,7 @@
 #include <map>
 
 #include "ash/shelf/shelf_delegate.h"
+#include "ash/shelf/shelf_layout_manager_observer.h"
 #include "mash/shelf/public/interfaces/shelf.mojom.h"
 #include "mash/wm/public/interfaces/shelf_layout.mojom.h"
 #include "mash/wm/public/interfaces/user_window_controller.mojom.h"
@@ -20,7 +21,10 @@ class ShelfModel;
 
 namespace sysui {
 
+// Manages communication between the ash_sysui shelf, the window manager, and
+// the browser.
 class ShelfDelegateMus : public ShelfDelegate,
+                         public ShelfLayoutManagerObserver,
                          public mash::shelf::mojom::ShelfController,
                          public mash::wm::mojom::UserWindowObserver {
  public:
@@ -40,6 +44,12 @@ class ShelfDelegateMus : public ShelfDelegate,
   bool IsAppPinned(const std::string& app_id) override;
   void UnpinAppWithID(const std::string& app_id) override;
 
+  // ShelfLayoutManagerObserver:

[msw, 2016/05/24 20:46:55]

I wonder if this should be done through ShelfDelegate instead?
(that might reduce our reliance upon the ash ShelfLayoutManager)

[James Cook, 2016/05/25 00:25:43]

Done.

+  void DidChangeVisibilityState(ShelfLayoutManager* layout_manager,
+                                ShelfVisibilityState new_state) override;
+  void OnAutoHideStateChanged(ShelfLayoutManager* layout_manager,
+                              ShelfAutoHideState new_state) override;
+
   // mash::shelf::mojom::ShelfController:
   void AddObserver(
       mash::shelf::mojom::ShelfObserverAssociatedPtrInfo observer) override;