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

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

Index: chrome/browser/ui/cocoa/passwords/passwords_bubble_controller.mm
diff --git a/chrome/browser/ui/cocoa/passwords/passwords_bubble_controller.mm b/chrome/browser/ui/cocoa/passwords/passwords_bubble_controller.mm
index 5877df793ee868dc2443363cd131bfa2f3ead41d..d6df328d5639db6b84eeccd5f14be1511163e7ea 100644
--- a/chrome/browser/ui/cocoa/passwords/passwords_bubble_controller.mm
+++ b/chrome/browser/ui/cocoa/passwords/passwords_bubble_controller.mm
@@ -52,6 +52,8 @@
 
 - (void)close {
   [currentController_ bubbleWillDisappear];
+  // The bubble is about to be closed. It destroys the model.
+  model_ = nil;
   [super close];
 }
 
@@ -60,13 +62,11 @@
   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]
@@ -148,6 +148,10 @@
   [self close];
 }
 
+- (ManagePasswordsBubbleModel*)model {
+  return model_;
+}
+
 @end
 
 @implementation ManagePasswordsBubbleController (Testing)