Fix reentrancy in HandleEvent by posting a task

BUG=none
TEST=pepper flash, run it and move the mouse everywhere.

Review URL: http://codereview.chromium.org/6260057

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@73475 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 9 insertions, 3 deletions

diff --git a/ppapi/proxy/ppp_instance_proxy.cc b/ppapi/proxy/ppp_instance_proxy.cc
index 144e3a1..6dabe99 100644
--- a/ppapi/proxy/ppp_instance_proxy.cc
+++ b/ppapi/proxy/ppp_instance_proxy.cc
@@ -58,9 +58,15 @@ void DidChangeFocus(PP_Instance instance, PP_Bool 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 synchronous call to the renderer. This will force any
+  // synchronous calls from the plugin to complete before processing this
+  // message. We avoid deadlock by never un-setting the unblock flag on messages
+  // from the plugin to the renderer.
+  msg->set_unblock(false);
+  HostDispatcher::GetForInstance(instance)->Send(msg);
   return result;
 }