Fix randomly disappearing icons in app list recent view.

extensions/browser/extension_icon_image.h

Index: extensions/browser/extension_icon_image.h
diff --git a/extensions/browser/extension_icon_image.h b/extensions/browser/extension_icon_image.h
index 2698de2def28029b930abdf7485e551ed402aecf..66af9ec16373c75ae2c322bd95f652bd0ebfde74 100644
--- a/extensions/browser/extension_icon_image.h
+++ b/extensions/browser/extension_icon_image.h
@@ -77,6 +77,9 @@ class IconImage : public content::NotificationObserver {
   gfx::Image image() const { return image_; }
   const gfx::ImageSkia& image_skia() const { return image_skia_; }
 
+  // Returns true if icon is attached to existing extension.

[Devlin, 2017/04/15 00:42:54]

grammar nit: if *the* icon is attached to *an* existing extension.

[khmel, 2017/04/15 20:21:28]

Done.

+  bool is_valid() const { return extension_.get(); }
+
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);