PPAPI: Initialize CompletionCallbackWithOutput storage

ppapi/cpp/extensions/ext_output_traits.h

Index: ppapi/cpp/extensions/ext_output_traits.h
diff --git a/ppapi/cpp/extensions/ext_output_traits.h b/ppapi/cpp/extensions/ext_output_traits.h
index 08dc744c47d87e2f4ab53c50b2c0c2da33686df9..ed57be10d9841118d26225b46962c8ba909ab4a6 100644
--- a/ppapi/cpp/extensions/ext_output_traits.h
+++ b/ppapi/cpp/extensions/ext_output_traits.h
@@ -68,6 +68,8 @@ struct ExtCallbackOutputTraits {
   static inline T& StorageToPluginArg(StorageType& t) {
     return t.output();
   }
+
+  static inline void Initialize(StorageType* /* t */) {}
 };
 
 // This class provides storage for a PP_Var and a vector of objects which are
@@ -129,6 +131,8 @@ struct ExtCallbackOutputTraits< std::vector<T> > {
   static inline std::vector<T>& StorageToPluginArg(StorageType& t) {
     return t.output();
   }
+
+  static inline void Initialize(StorageType* /* t */) {}
 };
 
 }  // namespace internal