Emit error events if the loading of an object element failed

components/plugins/renderer/webview_plugin.cc

Index: components/plugins/renderer/webview_plugin.cc
diff --git a/components/plugins/renderer/webview_plugin.cc b/components/plugins/renderer/webview_plugin.cc
index 075515a0779ff784b51c27f377e22cf38aba4a59..7f66bca3d081076d118ab17fb79ea692fe7749fd 100644
--- a/components/plugins/renderer/webview_plugin.cc
+++ b/components/plugins/renderer/webview_plugin.cc
@@ -245,6 +245,18 @@ void WebViewPlugin::didFailLoading(const WebURLError& error) {
   error_.reset(new WebURLError(error));
 }
 
+void WebViewPlugin::markAsErrorPlaceholder() {
+  placeholder = true;
+}
+
+void WebViewPlugin::unmarkAsErrorPlaceholder() {
+  placeholder = false;
+}
+
+bool WebViewPlugin::isPlaceholder() {
+  return placeholder;
+}
+
 WebViewPlugin::WebViewHelper::WebViewHelper(
     WebViewPlugin* plugin,
     const WebPreferences& preferences) : plugin_(plugin) {