Don't try to use ManagePasswordsBubbleModel if the password bubble was closed.

chrome/browser/ui/cocoa/passwords/passwords_bubble_controller.mm

 // Copyright 2014 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.
 
 #import "chrome/browser/ui/cocoa/passwords/passwords_bubble_controller.h"
 
 #include "base/mac/scoped_nsobject.h"
 #include "chrome/browser/ui/browser_finder.h"
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 #import "chrome/browser/ui/cocoa/info_bubble_view.h"
@@ skipping 34 matching lines @@
   [super dealloc];
 }
 
 - (void)showWindow:(id)sender {
   [self performLayout];
   [super showWindow:sender];
 }
 
 - (void)close {
   [currentController_ bubbleWillDisappear];
+  // The bubble is about to be closed. It destroys the model.
+  model_ = nil;
   [super close];
 }
 
 - (void)updateState {
   // Find the next view controller.
   currentController_.reset();
   if (model_->state() == password_manager::ui::PENDING_PASSWORD_STATE) {
     currentController_.reset([[SavePendingPasswordViewController alloc]
-        initWithModel:model_
-             delegate:self]);
+        initWithDelegate:self]);
   } else if (model_->state() ==
              password_manager::ui::PENDING_PASSWORD_UPDATE_STATE) {
     currentController_.reset([[UpdatePendingPasswordViewController alloc]
-        initWithModel:model_
-             delegate:self]);
+        initWithDelegate:self]);
   } else if (model_->state() == password_manager::ui::CONFIRMATION_STATE) {
     currentController_.reset(
         [[ManagePasswordsBubbleConfirmationViewController alloc]
             initWithModel:model_
                  delegate:self]);
   } else if (model_->state() == password_manager::ui::MANAGE_STATE) {
     currentController_.reset(
         [[ManagePasswordsBubbleManageViewController alloc]
             initWithModel:model_
                  delegate:self]);
@@ skipping 61 matching lines @@
            display:YES
            animate:[window isVisible]];
 }
 
 #pragma mark ManagePasswordsBubbleContentViewDelegate
 
 - (void)viewShouldDismiss {
   [self close];
 }
 
+- (ManagePasswordsBubbleModel*)model {
+  return model_;
+}
+
 @end
 
 @implementation ManagePasswordsBubbleController (Testing)
 
 - (NSViewController*)currentController {
   return currentController_.get();
 }
 
 @end