Hide/show widget on Windows screen lock/unlock

ui/views/widget/native_widget_delegate.h

 // Copyright (c) 2012 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 UI_VIEWS_WIDGET_NATIVE_WIDGET_DELEGATE_H_
 #define UI_VIEWS_WIDGET_NATIVE_WIDGET_DELEGATE_H_
 
 #include <vector>
 
 #include "ui/events/event_constants.h"
@@ skipping 49 matching lines @@
   // Called when native focus moves from one native view to another.
   virtual void OnNativeFocus() = 0;
   virtual void OnNativeBlur() = 0;
 
   // Called when the window is about to be shown/hidden.
   virtual void OnNativeWidgetVisibilityChanging(bool visible) = 0;
 
   // Called when the window is shown/hidden.
   virtual void OnNativeWidgetVisibilityChanged(bool visible) = 0;
 
+  // Some OSs (e.g. Windows and Linux) don't mark windows as hiden on screen
+  // lock or when other opaque windows fully cover them.
+  // Note that e.g. OSX and Android do this while Windows and Linux don't.
+  // OnSoftVisibilityChanged enables that OS window state is kept as is (on
+  // Linux and Windows) and that e.g. power saving PageVisibility API is still
+  // properly triggered.
+  virtual void OnSoftVisibilityChanged(bool visible) = 0;
+
   // Called when the native widget is created.
   // The |desktop_widget| bool is true for widgets created in the desktop and
   // false for widgets created in the shell.
   virtual void OnNativeWidgetCreated(bool desktop_widget) = 0;
 
   // Called just before the native widget is destroyed. This is the delegate's
   // last chance to do anything with the native widget handle.
   virtual void OnNativeWidgetDestroying() = 0;
 
   // Called just after the native widget is destroyed.
@@ skipping 63 matching lines @@
   // later.  Returns true if the initial focus has been set or the window should
   // not set the initial focus, or false if the caller should set the initial
   // focus (if any).
   virtual bool SetInitialFocus(ui::WindowShowState show_state) = 0;
 };
 
 }  // namespace internal
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_NATIVE_WIDGET_DELEGATE_H_