Give up focus if the focused view becomes unfocusable

ui/views/focus/focus_manager.cc

Index: ui/views/focus/focus_manager.cc
diff --git a/ui/views/focus/focus_manager.cc b/ui/views/focus/focus_manager.cc
index f52712e62344846226c5aaf819b8f1e7146b63c2..5f021f94a631a501932cfab6219dd791010a6c7a 100644
--- a/ui/views/focus/focus_manager.cc
+++ b/ui/views/focus/focus_manager.cc
@@ -353,6 +353,14 @@ void FocusManager::ClearFocus() {
   SetStoredFocusView(focused_view);
 }
 
+void FocusManager::ReviseFocusedView() {
+  if (focused_view_ && !focused_view_->IsAccessibilityFocusable()) {
+    AdvanceFocus(false);
+    if (focused_view_ && !focused_view_->IsAccessibilityFocusable())
+      ClearFocus();
+  }
+}
+
 void FocusManager::StoreFocusedView(bool clear_native_focus) {
   View* focused_view = focused_view_;
   // Don't do anything if no focused view. Storing the view (which is NULL), in