Check if BubbleReference weak pointer is valid before using it in the chooser

chrome/browser/ui/views/website_settings/chooser_bubble_ui_view.cc

 // Copyright 2015 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 "chrome/browser/ui/views/website_settings/chooser_bubble_ui_view.h"
 
 #include <stddef.h>
 
 #include <memory>
 
@@ skipping 111 matching lines @@
 views::View* ChooserBubbleUiViewDelegate::CreateExtraView() {
   return chooser_content_view_->CreateExtraView();
 }
 
 views::View* ChooserBubbleUiViewDelegate::CreateFootnoteView() {
   return chooser_content_view_->CreateFootnoteView();
 }
 
 bool ChooserBubbleUiViewDelegate::Accept() {
   chooser_content_view_->Accept();
-  bubble_reference_->CloseBubble(BUBBLE_CLOSE_ACCEPTED);
+  if (bubble_reference_)
+    bubble_reference_->CloseBubble(BUBBLE_CLOSE_ACCEPTED);
   return true;
 }
 
 bool ChooserBubbleUiViewDelegate::Cancel() {
   chooser_content_view_->Cancel();
-  bubble_reference_->CloseBubble(BUBBLE_CLOSE_CANCELED);
+  if (bubble_reference_)
+    bubble_reference_->CloseBubble(BUBBLE_CLOSE_CANCELED);
   return true;
 }
 
 bool ChooserBubbleUiViewDelegate::Close() {
   chooser_content_view_->Close();
   return true;
 }
 
 views::View* ChooserBubbleUiViewDelegate::GetContentsView() {
   return chooser_content_view_;
@@ skipping 79 matching lines @@
     return browser_view->exclusive_access_bubble()->GetView();
 
   return browser_view->top_container();
 }
 
 views::BubbleBorder::Arrow ChooserBubbleUiView::GetAnchorArrow() {
   if (browser_->SupportsWindowFeature(Browser::FEATURE_LOCATIONBAR))
     return views::BubbleBorder::TOP_LEFT;
   return views::BubbleBorder::NONE;
 }