Give up focus if the focused view becomes unfocusable

ui/views/controls/combobox/combobox.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/controls/combobox/combobox.h"
 
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
 #include "grit/ui_resources.h"
 #include "ui/base/accessibility/accessible_view_state.h"
@@ skipping 82 matching lines @@
     : model_(model),
       listener_(NULL),
       selected_index_(model_->GetDefaultIndex()),
       invalid_(false),
       text_border_(new FocusableBorder()),
       disclosure_arrow_(ui::ResourceBundle::GetSharedInstance().GetImageNamed(
           IDR_MENU_DROPARROW).ToImageSkia()),
       dropdown_open_(false) {
   model_->AddObserver(this);
   UpdateFromModel();
-  set_focusable(true);
+  SetFocusable(true);
   set_border(text_border_);
 }
 
 Combobox::~Combobox() {
   model_->RemoveObserver(this);
 }
 
 // static
 const gfx::Font& Combobox::GetFont() {
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
@@ skipping 361 matching lines @@
 
 int Combobox::MenuCommandToIndex(int menu_command_id) const {
   // (note that the id received is offset by kFirstMenuItemId)
   // Revert menu ID offset to map back to combobox model.
   int index = menu_command_id - kFirstMenuItemId;
   DCHECK_LT(index, model()->GetItemCount());
   return index;
 }
 
 }  // namespace views