Bug 563737 - [QT] Detect when Qt plugins enter a nested event loop. r=cjones

dom/plugins/PluginModuleParent.cpp

@@ -39,6 +39,10 @@
 #ifdef MOZ_WIDGET_GTK2
 #include <glib.h>
 #endif
+#ifdef MOZ_WIDGET_QT
+#include <QtCore/QCoreApplication>
+#include <QtCore/QEventLoop>
+#endif
 
 #include "base/process_util.h"
 
@@ -754,7 +758,20 @@ PluginModuleParent::AnswerNPN_GetValue_WithBoolReturn(const NPNVariable& aVariab
     return true;
 }
 
-#if !defined(MOZ_WIDGET_GTK2)
+#if defined(MOZ_WIDGET_QT)
+static const int kMaxtimeToProcessEvents = 30;
+bool
+PluginModuleParent::AnswerProcessSomeEvents()
+{
+    PLUGIN_LOG_DEBUG(("Spinning mini nested loop ..."));
+    QCoreApplication::processEvents(QEventLoop::AllEvents, kMaxtimeToProcessEvents);
+
+    PLUGIN_LOG_DEBUG(("... quitting mini nested loop"));
+
+    return true;
+}
+
+#elif !defined(MOZ_WIDGET_GTK2)
 bool
 PluginModuleParent::AnswerProcessSomeEvents()
 {