MacViews: Exploring removal of window-modal sheets.

chrome/browser/ui/cocoa/web_contents_modal_dialog_host_cocoa.h

 // Copyright 2015 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 CHROME_BROWSER_UI_COCOA_WEB_CONTENTS_DIALOG_HOST_COCOA_H_
 #define CHROME_BROWSER_UI_COCOA_WEB_CONTENTS_DIALOG_HOST_COCOA_H_
 
 #include "base/macros.h"
+#include "base/observer_list.h"
 #include "components/web_modal/web_contents_modal_dialog_host.h"
 
 @class ConstrainedWindowSheetController;
 
 // In a Cocoa browser, the modal dialog host is a simple bridge to the
 // ConstrainedWindowSheetController to get the dialog size and parent window.
 class WebContentsModalDialogHostCocoa
     : public web_modal::WebContentsModalDialogHost {
  public:
   explicit WebContentsModalDialogHostCocoa(
       ConstrainedWindowSheetController* sheet_controller);
   ~WebContentsModalDialogHostCocoa() override;
 
+  void OnPositionRequiresUpdate();
+
   // web_modal::ModalDialogHost:
   gfx::NativeView GetHostView() const override;
   gfx::Point GetDialogPosition(const gfx::Size& size) override;
+  gfx::Point GetHostPosition() const override;
   void AddObserver(web_modal::ModalDialogHostObserver* observer) override;
   void RemoveObserver(web_modal::ModalDialogHostObserver* observer) override;
 
   // web_modal::WebContentsModalDialogHost:
   gfx::Size GetMaximumDialogSize() override;
 
  private:
   ConstrainedWindowSheetController* sheet_controller_;  // Weak. Owns |this|.
+  base::ObserverList<web_modal::ModalDialogHostObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsModalDialogHostCocoa);
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_WEB_CONTENTS_DIALOG_HOST_COCOA_H_