Add kAccessibilityFocusFallsbackToWidget property

ui/views/widget/widget.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/widget/widget.h"
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 313 matching lines @@
     params.activatable = InitParams::ACTIVATABLE_NO;
   }
 
   widget_delegate_ = params.delegate ?
       params.delegate : new DefaultWidgetDelegate(this);
   widget_delegate_->set_can_activate(can_activate);
 
   ownership_ = params.ownership;
   native_widget_ = CreateNativeWidget(params, this)->AsNativeWidgetPrivate();
   root_view_.reset(CreateRootView());
+  // Make root view of widget accessibility focusable as automation can fire
+  // focus change event to it.
+  root_view_->SetFocusBehavior(View::FocusBehavior::ACCESSIBLE_ONLY);

[sky, 2016/12/01 00:36:59]

Again, might this result in trying to focus widgets that we normally don't want
focused?

[yawano, 2016/12/01 00:47:08]

Yes.

   default_theme_provider_.reset(new ui::DefaultThemeProvider);
   if (params.type == InitParams::TYPE_MENU) {
     is_mouse_button_pressed_ =
         internal::NativeWidgetPrivate::IsMouseButtonDown();
   }
   native_widget_->InitNativeWidget(params);
   if (RequiresNonClientView(params.type)) {
     non_client_view_ = new NonClientView;
     non_client_view_->SetFrameView(CreateNonClientFrameView());
     // Create the ClientView, add it to the NonClientView and add the
@@ skipping 1150 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // internal::NativeWidgetPrivate, NativeWidget implementation:
 
 internal::NativeWidgetPrivate* NativeWidgetPrivate::AsNativeWidgetPrivate() {
   return this;
 }
 
 }  // namespace internal
 }  // namespace views