Introduce the MicButtonTargeter class

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index 54d6d7d2d49538acfd74dfd28516eb31ee637434..dc9b67edcc9d74b4d759a3d43c111fa0bdb251d4 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -1115,6 +1115,10 @@ ui::EventTargeter* View::GetEventTargeter() {
   return targeter_.get();
 }
 
+const ui::EventTargeter* View::GetEventTargeter() const {
+  return targeter_.get();
+}
+
 void View::ConvertEventToTarget(ui::EventTarget* target,
                                 ui::LocatedEvent* event) {
   event->ConvertLocationToTarget(this, static_cast<View*>(target));