PPAPI: Implement synchronous postMessage

content/renderer/pepper/message_channel.h

 // 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.
 
 #ifndef CONTENT_RENDERER_PEPPER_MESSAGE_CHANNEL_H_
 #define CONTENT_RENDERER_PEPPER_MESSAGE_CHANNEL_H_
 
 #include <deque>
 #include <list>
 #include <map>
@@ skipping 42 matching lines @@
   explicit MessageChannel(PepperPluginInstanceImpl* instance);
   ~MessageChannel();
 
   // Post a message to the onmessage handler for this channel's instance
   // asynchronously.
   void PostMessageToJavaScript(PP_Var message_data);
 
   // Post a message to the plugin's HandleMessage function for this channel's
   // instance.
   void PostMessageToNative(const NPVariant* message_data);
+  // Post a message to the plugin's HandleBlocking Message function for this
+  // channel's instance synchronously, and return a result.
+  void PostBlockingMessageToNative(const NPVariant* message_data,
+                                   NPVariant* np_result);
 
   // Return the NPObject* to which we should forward any calls which aren't
   // related to postMessage.  Note that this can be NULL;  it only gets set if
   // there is a scriptable 'InstanceObject' associated with this channel's
   // instance.
   NPObject* passthrough_object() { return passthrough_object_; }
   void SetPassthroughObject(NPObject* passthrough);
 
   NPObject* np_object() { return np_object_; }
 
@@ skipping 62 matching lines @@
   // This is used to ensure pending tasks will not fire after this object is
   // destroyed.
   base::WeakPtrFactory<MessageChannel> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageChannel);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_MESSAGE_CHANNEL_H_