Linux UI: Add IsVisibleOnAllWorkspaces()

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 62b4b56680940483f338c2a56a1222da3279f264..eebeb87db63cc3c2553bee4b98bbacff3a5f844c 100644
--- a/ui/views/widget/widget.cc
+++ b/ui/views/widget/widget.cc
@@ -666,6 +666,10 @@ void Widget::SetVisibleOnAllWorkspaces(bool always_visible) {
   native_widget_->SetVisibleOnAllWorkspaces(always_visible);
 }
 
+bool Widget::IsVisibleOnAllWorkspaces() const {
+  return native_widget_->IsVisibleOnAllWorkspaces();
+}
+
 void Widget::Maximize() {
   native_widget_->Maximize();
 }