ObserverList::HasObserver now takes a const pointer.

ui/views/widget/widget.cc

Index: ui/views/widget/widget.cc
diff --git a/ui/views/widget/widget.cc b/ui/views/widget/widget.cc
index a642448bcfd9b47ef04da150e01c3e3c1a7a4e76..acce831d938dcc0aecca9e03cf974252b88aa067 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -390,7 +390,7 @@ void Widget::RemoveObserver(WidgetObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
-bool Widget::HasObserver(WidgetObserver* observer) {
+bool Widget::HasObserver(const WidgetObserver* observer) const {
   return observers_.HasObserver(observer);
 }
 
@@ -402,7 +402,7 @@ void Widget::RemoveRemovalsObserver(WidgetRemovalsObserver* observer) {
   removals_observers_.RemoveObserver(observer);
 }
 
-bool Widget::HasRemovalsObserver(WidgetRemovalsObserver* observer) {
+bool Widget::HasRemovalsObserver(const WidgetRemovalsObserver* observer) const {
   return removals_observers_.HasObserver(observer);
 }