linux: cleanup browser-side GtkSockets when plugins are destroyed

webkit/tools/test_shell/test_webview_delegate_gtk.cc

Index: webkit/tools/test_shell/test_webview_delegate_gtk.cc
diff --git a/webkit/tools/test_shell/test_webview_delegate_gtk.cc b/webkit/tools/test_shell/test_webview_delegate_gtk.cc
index 74586e524ea18f84e421a562934c99fcf63a33cb..cd21c176dd013cdd828d45e9f720cc77319a716d 100644
--- a/webkit/tools/test_shell/test_webview_delegate_gtk.cc
+++ b/webkit/tools/test_shell/test_webview_delegate_gtk.cc
@@ -98,6 +98,10 @@ WebPluginDelegate* TestWebViewDelegate::CreatePluginDelegate(
   return WebPluginDelegateImpl::Create(info.path, mtype, plugin_parent);
 }
 
+void TestWebViewDelegate::WillDestroyPluginWindow(unsigned long id) {
+  shell_->webViewHost()->OnPluginWindowDestroyed(id);
+}
+
 void TestWebViewDelegate::ShowJavaScriptAlert(const std::wstring& message) {
   GtkWidget* dialog = gtk_message_dialog_new(
       shell_->mainWnd(), GTK_DIALOG_MODAL, GTK_MESSAGE_INFO,