ExtensionInfobarGtk doesn't handle delegate going away.

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

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/ui/gtk/infobars/extension_infobar_gtk.h"
 
 #include "base/debug/trace_event.h"
 #include "chrome/browser/extensions/extension_context_menu_model.h"
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/extensions/image_loader.h"
@@ skipping 15 matching lines @@
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/gtk_util.h"
 #include "ui/gfx/image/image.h"
 
 ExtensionInfoBarGtk::ExtensionInfoBarGtk(InfoBarService* owner,
                                          ExtensionInfoBarDelegate* delegate)
     : InfoBarGtk(owner, delegate),
       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
   // extensions_infobar.css, and the close button provided by some GTK+ themes
   // won't look good on this background.
   close_button_->ForceChromeTheme();
 
   int height = delegate->height();
   SetBarTargetHeight((height > 0) ? (height + kSeparatorLineHeight) : 0);
 
   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
   // owning container.
   gtk_container_remove(GTK_CONTAINER(alignment_), view_->native_view());
 }
 
 void ExtensionInfoBarGtk::GetTopColor(InfoBarDelegate::Type type,
                                       double* r, double* g, double* b) {
   // Extension infobars are always drawn with chrome-theme colors.
@@ skipping 81 matching lines @@
   Signals()->Connect(view_->native_view(), "expose-event",
                      G_CALLBACK(&OnExposeThunk), this);
   Signals()->Connect(view_->native_view(), "size_allocate",
                      G_CALLBACK(&OnSizeAllocateThunk), this);
 }
 
 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_);
   if (!parent)
     return NULL;
 
   return BrowserWindowGtk::GetBrowserWindowForNativeWindow(parent)->browser();
 }
 
 ExtensionContextMenuModel* ExtensionInfoBarGtk::BuildMenuModel() {
@@ skipping 39 matching lines @@
   // We also need to draw our infobar arrows over the renderer.
   static_cast<InfoBarContainerGtk*>(container())->
       PaintInfobarBitsOn(sender, event, this);
 
   return FALSE;
 }
 
 InfoBar* ExtensionInfoBarDelegate::CreateInfoBar(InfoBarService* owner) {
   return new ExtensionInfoBarGtk(owner, this);
 }