Fix reentrancy in HandleInputEvent by posting a task

ppapi/proxy/ppp_instance_proxy.cc

 // Copyright (c) 2010 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/proxy/ppp_instance_proxy.h"
 
 #include <algorithm>
 
 #include "ppapi/c/pp_var.h"
 #include "ppapi/c/ppp_instance.h"
@@ skipping 39 matching lines @@
 
 void DidChangeFocus(PP_Instance instance, PP_Bool has_focus) {
   HostDispatcher::GetForInstance(instance)->Send(
       new PpapiMsg_PPPInstance_DidChangeFocus(INTERFACE_ID_PPP_INSTANCE,
                                               instance, has_focus));
 }
 
 PP_Bool HandleInputEvent(PP_Instance instance,
                          const PP_InputEvent* event) {
   PP_Bool result = PP_FALSE;
-  HostDispatcher::GetForInstance(instance)->Send(
-      new PpapiMsg_PPPInstance_HandleInputEvent(INTERFACE_ID_PPP_INSTANCE,
-                                                instance, *event, &result));
+  IPC::Message* msg = new PpapiMsg_PPPInstance_HandleInputEvent(
+      INTERFACE_ID_PPP_INSTANCE, instance, *event, &result);
+  // Make this message not unblock, to avoid re-entrancy problems when the
+  // plugin does a sync call to the renderer.

[brettw, 2011/02/02 05:00:08]

Can you add something like: "This will force any synchronous calls from the
plugin to complete before processing this message. We avoid deadlock by never
"setting unblock" on messages from the plugin to the renderer."

+  msg->set_unblock(false);
+  HostDispatcher::GetForInstance(instance)->Send(msg);
   return result;
 }
 
 PP_Bool HandleDocumentLoad(PP_Instance instance,
                            PP_Resource url_loader) {
   PP_Bool result = PP_FALSE;
   HostResource serialized_loader;
   serialized_loader.SetHostResource(instance, url_loader);
   HostDispatcher::GetForInstance(instance)->Send(
       new PpapiMsg_PPPInstance_HandleDocumentLoad(INTERFACE_ID_PPP_INSTANCE,
@@ skipping 119 matching lines @@
 
 void PPP_Instance_Proxy::OnMsgGetInstanceObject(
     PP_Instance instance,
     SerializedVarReturnValue result) {
   result.Return(dispatcher(),
                 ppp_instance_target()->GetInstanceObject(instance));
 }
 
 }  // namespace proxy
 }  // namespace pp