Fix crash bug in save card bubble on Mac.

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

Index: chrome/browser/ui/cocoa/autofill/save_card_bubble_view_bridge.mm
diff --git a/chrome/browser/ui/cocoa/autofill/save_card_bubble_view_bridge.mm b/chrome/browser/ui/cocoa/autofill/save_card_bubble_view_bridge.mm
index 051bd0b8f981242e4a29cbe1da54eda89cc0c9bd..ab08a77ccb93a7a30daa3efdfe14c8a51ae50998 100644
--- a/chrome/browser/ui/cocoa/autofill/save_card_bubble_view_bridge.mm
+++ b/chrome/browser/ui/cocoa/autofill/save_card_bubble_view_bridge.mm
@@ -99,11 +99,13 @@ void SaveCardBubbleViewBridge::OnBubbleClosed() {
 }
 
 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];
 }