Convert the PluginService interface to be an async wrapper around PluginList.

chrome/browser/plugin_exceptions_table_model.h

Index: chrome/browser/plugin_exceptions_table_model.h
diff --git a/chrome/browser/plugin_exceptions_table_model.h b/chrome/browser/plugin_exceptions_table_model.h
index 9f376210b5bbb1a05ea705357d058e2c567b6977..7c4bb1c0b975ba0a2aea76ad4ef91ea64e261530 100644
--- a/chrome/browser/plugin_exceptions_table_model.h
+++ b/chrome/browser/plugin_exceptions_table_model.h
@@ -15,6 +15,12 @@
 #include "content/common/notification_observer.h"
 #include "webkit/plugins/npapi/plugin_list.h"
 
+namespace webkit {
+namespace npapi {
+class PluginGroup;
+}
+}
+
 class PluginExceptionsTableModel : public RemoveRowsTableModel,
                                    public NotificationObserver {
  public: