Emit error events if the loading of an object element failed

third_party/WebKit/public/web/WebPlugin.h

 /*
  * Copyright (C) 2009, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2014 Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 221 matching lines @@
 
   // View rotation types.
   enum RotationType {
     kRotationType90Clockwise,
     kRotationType90Counterclockwise
   };
   // Whether the plugin can rotate the view of its content.
   virtual bool CanRotateView() { return false; }
   // Rotates the plugin's view of its content.
   virtual void RotateView(RotationType type) {}
-
+  // Check whether a plugin can be interacted with. A positive return value
+  // means the plugin has not loaded and hence cannot be interacted with.
+  // The plugin could, however, load successfully later.
   virtual bool IsPlaceholder() { return true; }
+  // Check whether a plugin failed to load, with there being no possibility of
+  // it loading later.
+  virtual bool IsErrorPlaceholder() { return false; }
 
  protected:
   ~WebPlugin() {}
 };
 
 }  // namespace blink
 
 #endif