ExtensionInfobarGtk doesn't handle delegate going away.

chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc

Index: chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc
diff --git a/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc b/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc
index c69b5ded277b53494ba18b852e23002b5adf1689..b8336e0ccabf3d4553ea9f2608cf9b503c234f80 100644
--- a/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc
+++ b/chrome/browser/ui/gtk/infobars/extension_infobar_gtk.cc
@@ -33,6 +33,8 @@ ExtensionInfoBarGtk::ExtensionInfoBarGtk(InfoBarService* owner,
       delegate_(delegate),
       view_(NULL),
       ALLOW_THIS_IN_INITIALIZER_LIST(weak_ptr_factory_(this)) {
+  delegate->set_observer(this);
+
   // Always render the close button as if we were doing chrome style widget
   // rendering. For extension infobars, we force chrome style rendering because
   // extension authors are going to expect to match the declared gradient in
@@ -46,7 +48,10 @@ ExtensionInfoBarGtk::ExtensionInfoBarGtk(InfoBarService* owner,
   BuildWidgets();
 }
 
-ExtensionInfoBarGtk::~ExtensionInfoBarGtk() {}
+ExtensionInfoBarGtk::~ExtensionInfoBarGtk() {
+  if (delegate_)
+    delegate_->set_observer(NULL);
+}
 
 void ExtensionInfoBarGtk::PlatformSpecificHide(bool animate) {
   // This view is not owned by us; we can't unparent it because we aren't the
@@ -148,6 +153,10 @@ void ExtensionInfoBarGtk::StoppedShowing() {
   gtk_chrome_button_unset_paint_state(GTK_CHROME_BUTTON(button_));
 }
 
+void ExtensionInfoBarGtk::OnDelegateDeleted() {
+  delegate_ = NULL;
+}
+
 Browser* ExtensionInfoBarGtk::GetBrowser() {
   // Get the Browser object this infobar is attached to.
   GtkWindow* parent = platform_util::GetTopLevel(icon_);