Reland: mus: Enable system modal windows

components/mus/ws/window_manager_state.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_MUS_WS_WINDOW_MANAGER_STATE_H_
 #define COMPONENTS_MUS_WS_WINDOW_MANAGER_STATE_H_
 
 #include <stdint.h>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 64 matching lines @@
   }
 
   // Checks if |modal_window| is a visible modal window that blocks current
   // capture window and if that's the case, releases the capture.
   void ReleaseCaptureBlockedByModalWindow(const ServerWindow* modal_window);
 
   // Checks if the current capture window is blocked by any visible modal window
   // and if that's the case, releases the capture.
   void ReleaseCaptureBlockedByAnyModalWindow();
 
+  bool SetSystemModalWindow(ServerWindow* window);
+  ServerWindow* system_modal_window() {
+    return event_dispatcher_.system_modal_window();
+  }
+  const ServerWindow* system_modal_window() const {
+    return event_dispatcher_.system_modal_window();
+  }
+
   // Returns true if this is the WindowManager of the active user.
   bool IsActive() const;
 
   // TODO(sky): EventDispatcher is really an implementation detail and should
   // not be exposed.
   EventDispatcher* event_dispatcher() { return &event_dispatcher_; }
 
   void Activate(const gfx::Point& mouse_location_on_screen);
   void Deactivate();
 
@@ skipping 93 matching lines @@
 
   EventDispatcher event_dispatcher_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManagerState);
 };
 
 }  // namespace ws
 }  // namespace mus
 
 #endif  // COMPONENTS_MUS_WS_WINDOW_MANAGER_STATE_H_