Fix a crash in PageActionImageView when extensions are reloaded due to incognito settings changing.

chrome/browser/ui/views/location_bar/page_action_image_view.cc

Index: chrome/browser/ui/views/location_bar/page_action_image_view.cc
===================================================================
--- chrome/browser/ui/views/location_bar/page_action_image_view.cc	(revision 108847)
+++ chrome/browser/ui/views/location_bar/page_action_image_view.cc	(working copy)
@@ -13,8 +13,13 @@
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/location_bar/location_bar_view.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_action.h"
 #include "chrome/common/extensions/extension_resource.h"
+#include "content/browser/notification_service_impl.h"
+#include "content/public/browser/notification_details.h"
+#include "content/public/browser/notification_source.h"
 #include "ui/base/accessibility/accessible_view_state.h"
 #include "views/controls/menu/menu_item_view.h"
 #include "views/controls/menu/menu_model_adapter.h"
@@ -47,6 +52,10 @@
                        ImageLoadingTracker::DONT_CACHE);
   }
 
+  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
+                 content::Source<Profile>(
+                     owner_->browser()->profile()->GetOriginalProfile()));
+
   set_accessibility_focusable(true);
 }
 
@@ -225,8 +234,8 @@
 }
 
 void PageActionImageView::InspectPopup(ExtensionAction* action) {
-  ExecuteAction(1,  // left-click
-                true);  // inspect_with_devtools
+  ExecuteAction(1,      // Left-click.
+                true);  // |inspect_with_devtools|.
 }
 
 void PageActionImageView::ExtensionPopupIsClosing(ExtensionPopup* popup) {
@@ -235,6 +244,16 @@
   popup_ = NULL;
 }
 
+void PageActionImageView::Observe(int type,
+                                  const content::NotificationSource& source,
+                                  const content::NotificationDetails& details) {
+  DCHECK_EQ(chrome::NOTIFICATION_EXTENSION_UNLOADED, type);
+  const Extension* unloaded_extension =
+      content::Details<UnloadedExtensionInfo>(details)->extension;
+  if (page_action_ == unloaded_extension ->page_action())
+    owner_->UpdatePageActions();
+}
+
 void PageActionImageView::HidePopup() {
   if (popup_)
     popup_->Close();