events: Change gesture-event handler in EventHandler to not return any values.

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

Index: ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
index 87b8bf1f556d10d65e48e4476d028d04e40475a8..870b87802ca4a229d8322756d524cafc38c1b242 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
@@ -572,9 +572,8 @@ ui::EventResult DesktopNativeWidgetAura::OnTouchEvent(ui::TouchEvent* event) {
   return native_widget_delegate_->OnTouchEvent(event);
 }
 
-ui::EventResult DesktopNativeWidgetAura::OnGestureEvent(
-    ui::GestureEvent* event) {
-  return native_widget_delegate_->OnGestureEvent(event);
+void DesktopNativeWidgetAura::OnGestureEvent(ui::GestureEvent* event) {
+  native_widget_delegate_->OnGestureEvent(event);
 }
 
 ////////////////////////////////////////////////////////////////////////////////