Fix randomly disappearing icons in app list recent view.

extensions/browser/extension_icon_image.h

 // Copyright 2014 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.
 
 #ifndef EXTENSIONS_BROWSER_EXTENSION_ICON_IMAGE_H_
 #define EXTENSIONS_BROWSER_EXTENSION_ICON_IMAGE_H_
 
 #include <map>
 #include <string>
 
@@ skipping 59 matching lines @@
             const Extension* extension,
             const ExtensionIconSet& icon_set,
             int resource_size_in_dip,
             const gfx::ImageSkia& default_icon,
             Observer* observer);
   ~IconImage() override;
 
   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);
 
  private:
   class Source;
 
   // Loads an image representation for the scale factor.
   // If the representation gets loaded synchronously, it is returned by this
   // method.
   // If representation loading is asynchronous, an empty image
@@ skipping 28 matching lines @@
   content::NotificationRegistrar registrar_;
 
   base::WeakPtrFactory<IconImage> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IconImage);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_ICON_IMAGE_H_