Pepper WebSocket API: Fix memory leak issue

ppapi/cpp/websocket.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/cpp/websocket.h"
 
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_macros.h"
 #include "ppapi/cpp/completion_callback.h"
 #include "ppapi/cpp/instance_handle.h"
@@ skipping 52 matching lines @@
   return get_interface<PPB_WebSocket_1_0>()->Close(
       pp_resource(), code, reason.pp_var(),
       callback.pp_completion_callback());
 }
 
 int32_t WebSocket::ReceiveMessage(Var* message,
     const CompletionCallback& callback) {
   if (!has_interface<PPB_WebSocket_1_0>())
     return PP_ERROR_BADRESOURCE;
 
+  // Initialize |message| to release old internal PP_Var of reused |message|.
+  if (message)
+    *message = Var();
+
   return get_interface<PPB_WebSocket_1_0>()->ReceiveMessage(
       pp_resource(), const_cast<PP_Var*>(&message->pp_var()),
       callback.pp_completion_callback());
 }
 
 int32_t WebSocket::SendMessage(const Var& message) {
   if (!has_interface<PPB_WebSocket_1_0>())
     return PP_ERROR_BADRESOURCE;
 
   return get_interface<PPB_WebSocket_1_0>()->SendMessage(
@@ skipping 56 matching lines @@
 
 Var WebSocket::GetURL() {
   if (!has_interface<PPB_WebSocket_1_0>())
     return Var();
 
   return Var(PASS_REF,
              get_interface<PPB_WebSocket_1_0>()->GetURL(pp_resource()));
 }
 
 }  // namespace pp