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 220 matching lines @@
   virtual void stopFind() {}
 
   // View rotation types.
   enum RotationType { RotationType90Clockwise, RotationType90Counterclockwise };
   // 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) {}
 
   virtual bool isPlaceholder() { return true; }
+  // Check whether a plugin load lead to the instantiation of a
+  // PluginPlaceholderBase derived plugin, which is not allowed

[Bernhard Bauer, 2017/03/31 09:25:20]

This is a layering violation, as Blink shouldn't know about Chrome code.

[George Joseph, 2017/04/03 00:22:34]

Done.

+  // to load later on. isPlaceholder() is used by the pepper

[Bernhard Bauer, 2017/03/31 09:25:20]

This sentence should be a comment on isPlaceholder, but it also violates the
layering. It also doesn't actually convey much more information than is already
in the name.

AFAIU, the big difference is that isPlaceholder() returns whether the plugin
can't be interacted with _right now_ but might load later, whereas
isErrorPlaceholder() returns whether the plugin will _never_ load (and therefore
we should emit the error event).

+  // webplugin implementation to check if a WebHelperPlugin
+  // did create a PlaceHolder Plugin.

[Bernhard Bauer, 2017/03/31 09:25:20]

Nit: capitalized weirdly (placeholder should be a single lowercased word, as
should plugin).

[George Joseph, 2017/04/03 00:22:34]

Done.

+  virtual bool isErrorPlaceholder() { return false; };

[Bernhard Bauer, 2017/03/31 09:25:21]

Nit: No semicolon after the closing brace.

[George Joseph, 2017/04/03 00:22:34]

Done.

 
  protected:
   ~WebPlugin() {}
 };
 
 }  // namespace blink
 
 #endif