Revert "chromeos: Fix shelf appearing at login screen under mash"

ash/common/wm_shell.h

Index: ash/common/wm_shell.h
diff --git a/ash/common/wm_shell.h b/ash/common/wm_shell.h
index 46e28b55e412cd92917549bf9f68f7c8b7ef65c9..70736519a79e7cb2b8db3c19b20d6d03770ff119 100644
--- a/ash/common/wm_shell.h
+++ b/ash/common/wm_shell.h
@@ -13,7 +13,6 @@
 #include "ash/ash_export.h"
 #include "ash/common/metrics/gesture_action_type.h"
 #include "ash/common/metrics/user_metrics_action.h"
-#include "ash/common/session/session_state_observer.h"
 #include "ash/common/wm/lock_state_observer.h"
 #include "base/observer_list.h"
 #include "components/ui_devtools/devtools_server.h"
@@ -102,7 +101,7 @@ class WindowState;
 }
 
 // Similar to ash::Shell. Eventually the two will be merged.
-class ASH_EXPORT WmShell : public SessionStateObserver {
+class ASH_EXPORT WmShell {
  public:
   // This is necessary for a handful of places that is difficult to plumb
   // through context.
@@ -357,6 +356,9 @@ class ASH_EXPORT WmShell : public SessionStateObserver {
   // Initializes the appropriate shelves. Does nothing for any existing shelves.
   void CreateShelf();
 
+  // Show shelf view if it was created hidden (before session has started).
+  void ShowShelf();
+
   void CreateShelfDelegate();
 
   // Called after maximize mode has started, windows might still animate though.
@@ -445,7 +447,7 @@ class ASH_EXPORT WmShell : public SessionStateObserver {
 
  protected:
   explicit WmShell(std::unique_ptr<ShellDelegate> shell_delegate);
-  ~WmShell() override;
+  virtual ~WmShell();
 
   base::ObserverList<ShellObserver>* shell_observers() {
     return &shell_observers_;
@@ -473,9 +475,6 @@ class ASH_EXPORT WmShell : public SessionStateObserver {
   void SetAcceleratorController(
       std::unique_ptr<AcceleratorController> accelerator_controller);
 
-  // SessionStateObserver:
-  void SessionStateChanged(session_manager::SessionState state) override;
-
  private:
   friend class AcceleratorControllerTest;
   friend class ScopedRootWindowForNewWindows;