Fix crash bug in save card bubble on Mac.

chrome/browser/ui/cocoa/autofill/save_card_bubble_view_bridge.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/autofill/save_card_bubble_view_bridge.h"
 
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/ui/autofill/save_card_bubble_controller.h"
 #include "chrome/browser/ui/chrome_style.h"
@@ skipping 80 matching lines @@
     controller_->OnLegalMessageLinkClicked(url);
 }
 
 void SaveCardBubbleViewBridge::OnBubbleClosed() {
   if (controller_)
     controller_->OnBubbleClosed();
 
   delete this;
 }
 
 void SaveCardBubbleViewBridge::Hide() {

[groby-ooo-7-16, 2016/08/10 19:49:35]

That means Hide() can be called several times? How does that happen, and could
that be an issue on Views as well?

[Justin Donnelly, 2016/08/11 15:41:15]

Well, to be honest, I can't say that I 100% understand what's going on with this
crash. That said, Hide is called from several locations here and in the
controller. They're designed to result in only one invocation but the sequence
of events is complicated. My hypothesis is that the controller is being deleted
concurrently with a navigation. Both of these call Hide.

As for Views, it has a different lifecycle. But it has similar defensive checks
on controller_:

https://cs.chromium.org/chromium/src/chrome/browser/ui/views/autofill/save_ca...

-  // SaveCardBubbleViewBridge::OnBubbleClosed won't be able to call
-  // OnBubbleClosed on the bubble controller since we null the reference to it
-  // below. So we need to call it here.
-  controller_->OnBubbleClosed();
-  controller_ = nullptr;
+  if (controller_) {
+    // SaveCardBubbleViewBridge::OnBubbleClosed won't be able to call
+    // OnBubbleClosed on the bubble controller since we null the reference to it
+    // below. So we need to call it here.
+    controller_->OnBubbleClosed();
+    controller_ = nullptr;
+  }
   [view_controller_ close];
 }
 
 }  // autofill
 
 #pragma mark SaveCardBubbleViewCocoa
 
 @interface SaveCardBubbleViewCocoa ()
 + (base::scoped_nsobject<NSTextField>)makeLabel:(NSString*)text;
 + (base::scoped_nsobject<NSTextView>)makeWrappingLabel:(NSString*)text
@@ skipping 309 matching lines @@
     }
   }
 
   // If none of the legal message links are the source of the click, the source
   // must be the learn more link.
   bridge_->OnLearnMoreClicked();
   return YES;
 }
 
 @end