Cache pending JS bridge sync IPC replies, and send in case of RenderFrame deletion.

content/browser/android/java/gin_java_bridge_dispatcher_host.h

 // Copyright 2014 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 CONTENT_BROWSER_ANDROID_JAVA_GIN_JAVA_BRIDGE_DISPATCHER_HOST_H_
 #define CONTENT_BROWSER_ANDROID_JAVA_GIN_JAVA_BRIDGE_DISPATCHER_HOST_H_
 
 #include <map>
 #include <set>
 
@@ skipping 96 matching lines @@
   // this set so that it doesn't get garbage collected while it's still
   // potentially in use. Although the set is managed native side, it's owned
   // and defined in Java so that pushing refs into it does not create new GC
   // roots that would prevent ContentViewCore from being garbage collected.
   JavaObjectWeakGlobalRef retained_object_set_;
   bool allow_object_contents_inspection_;
   GinJavaBoundObject::ObjectMap objects_;
   typedef std::map<std::string, GinJavaBoundObject::ObjectID> NamedObjectMap;
   NamedObjectMap named_objects_;
 
+  // Keep track of pending calls out to Java such that we can send a synchronous
+  // reply to the renderer waiting on the response should the RenderFrame be
+  // destroyed while the reply is pending.
+  // Only used on the UI thread.
+  typedef std::map<RenderFrameHost*, IPC::Message*> PendingReplyMap;
+  PendingReplyMap pending_replies_;
+
   DISALLOW_COPY_AND_ASSIGN(GinJavaBridgeDispatcherHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_JAVA_GIN_JAVA_BRIDGE_DISPATCHER_HOST_H_