athena: Add a minimized state for the home-card.

athena/home/public/home_card.h

Index: athena/home/public/home_card.h
diff --git a/athena/home/public/home_card.h b/athena/home/public/home_card.h
index 795e8ffa58b55ea2fc121f90c2a6dbdde539c5ca..8658d367643dbb09e619caabbb6a06fc28a59101 100644
--- a/athena/home/public/home_card.h
+++ b/athena/home/public/home_card.h
@@ -30,6 +30,10 @@ class ATHENA_EXPORT HomeCard {
     // HomeCard is visible smaller at the bottom of the screen as a supplemental
     // widget.
     VISIBLE_BOTTOM,
+
+    // HomeCard is minimized (i.e. a small UI element is displayed on screen
+    // that the user can interact with to bring up the BOTTOM or CENTERED view).
+    VISIBLE_MINIMIZED,
   };
 
   // Creates/deletes/gets the singleton object of the HomeCard
@@ -48,7 +52,8 @@ class ATHENA_EXPORT HomeCard {
   virtual void RegisterSearchProvider(
       app_list::SearchProvider* search_provider) = 0;
 
-  // Called when the virtual keyboard changed has changed to |bounds|.
+  // Called when the virtual keyboard changed has changed to |bounds|. An empty
+  // |bounds| indicates that the virtual keyboard is not visible anymore.
   virtual void UpdateVirtualKeyboardBounds(
       const gfx::Rect& bounds) = 0;
 };