Allow Widget to pass accelerator handling to its parent.

ui/views/widget/widget.h

Index: ui/views/widget/widget.h
diff --git a/ui/views/widget/widget.h b/ui/views/widget/widget.h
index aa89478dd50604acafdad03b842dbdbdafbaaa52..01bf6e131a6d4b92b7d9952de16c2d323f3e690c 100644
--- a/ui/views/widget/widget.h
+++ b/ui/views/widget/widget.h
@@ -66,6 +66,7 @@ class NativeWidget;
 class NonClientFrameView;
 class TooltipManager;
 class View;
+class WidgetAcceleratorHandlingDelegate;
 class WidgetDelegate;
 class WidgetObserver;
 class WidgetRemovalsObserver;
@@ -289,6 +290,8 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
     // be sent to the widget.
     bool wants_mouse_events_when_inactive = false;
 
+    bool pass_accelerator_to_parent = false;
+
     // A map of properties applied to windows when running in mus.
     std::map<std::string, std::vector<uint8_t>> mus_properties;
   };
@@ -391,6 +394,10 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
   // no accelerator associated with a given id, which is a common condition.
   virtual bool GetAccelerator(int cmd_id, ui::Accelerator* accelerator) const;
 
+  bool CanHandleAccelerators() const;
+  void AddHandleAcceleratorsOverride();
+  void RemoveHandleAcceleratorsOverride();
+
   // Forwarded from the RootView so that the widget can do any cleanup.
   void ViewHierarchyChanged(const View::ViewHierarchyChangedDetails& details);
 
@@ -969,6 +976,10 @@ class VIEWS_EXPORT Widget : public internal::NativeWidgetDelegate,
   // disabled.
   bool movement_disabled_;
 
+  std::unique_ptr<WidgetAcceleratorHandlingDelegate>
+      accelerator_handling_delegate_;
+  int handle_accelerators_override_count_ = 0;
+
   ScopedObserver<ui::NativeTheme, ui::NativeThemeObserver> observer_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);