Hold messages in message port service when a message port is

android_webview/native/aw_message_port_service_impl.h

 // Copyright 2015 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.
 
 #ifndef ANDROID_WEBVIEW_NATIVE_AW_MESSAGE_PORT_SERVICE_IMPL_H_
 #define ANDROID_WEBVIEW_NATIVE_AW_MESSAGE_PORT_SERVICE_IMPL_H_
 
 #include <jni.h>
 #include <map>
 
@@ skipping 27 matching lines @@
       const base::ListValue& message,
       const std::vector<int>& sent_message_port_ids) override;
   void OnMessagePortMessageFilterClosing(
       AwMessagePortMessageFilter* filter) override;
   void CleanupPort(int message_port_id) override;
 
   // Methods called from Java.
   void PostAppToWebMessage(JNIEnv* env, jobject object, int sender_id,
       jstring message, jintArray sent_ports);
   void ClosePort(JNIEnv* env, jobject object, int message_port_id);
+  void ReleaseMessages(JNIEnv* env, jobject object, int message_port_id);
 
   void RemoveSentPorts(const std::vector<int>& sent_ports);
 
 private:
   void PostAppToWebMessageOnIOThread(
       int sender_id,
       base::string16* message,
       std::vector<int>* sent_ports);
   void CreateMessageChannelOnIOThread(
       scoped_refptr<AwMessagePortMessageFilter> filter,
@@ skipping 11 matching lines @@
   MessagePorts ports_; // Access on IO thread
 
   DISALLOW_COPY_AND_ASSIGN(AwMessagePortServiceImpl);
 };
 
 bool RegisterAwMessagePortService(JNIEnv* env);
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_NATIVE_AW_MESSAGE_PORT_SERVICE_IMPL_H_