Add a11y virtual keyboard icon when a11y VK is enabled

ui/keyboard/keyboard_controller.cc

Index: ui/keyboard/keyboard_controller.cc
diff --git a/ui/keyboard/keyboard_controller.cc b/ui/keyboard/keyboard_controller.cc
index 09fb34b397f99e8a599e890c5437aa8bdfdcf8fc..542c0c3f048d4c8e62d0444bd52678c913ad002c 100644
--- a/ui/keyboard/keyboard_controller.cc
+++ b/ui/keyboard/keyboard_controller.cc
@@ -314,6 +314,11 @@ void KeyboardController::RemoveObserver(KeyboardControllerObserver* observer) {
   observer_list_.RemoveObserver(observer);
 }
 
+void KeyboardController::ShowAndLockKeyboard() {
+  set_lock_keyboard(true);
+  OnShowImeIfNeeded();
+}
+
 void KeyboardController::OnWindowHierarchyChanged(
     const HierarchyChangeParams& params) {
   if (params.new_parent && params.target == container_.get())