PPAPI: Never re-enter JavaScript for PostMessage.

ppapi/proxy/host_dispatcher.cc

Index: ppapi/proxy/host_dispatcher.cc
diff --git a/ppapi/proxy/host_dispatcher.cc b/ppapi/proxy/host_dispatcher.cc
index 8f3833f5ddff7fa8f6a8cec321b59911f77b60bb..9b357996d73a60157adce9309388b09b26f348f1 100644
--- a/ppapi/proxy/host_dispatcher.cc
+++ b/ppapi/proxy/host_dispatcher.cc
@@ -61,10 +61,10 @@ class BoolRestorer {
 
 HostDispatcher::HostDispatcher(PP_Module module,
                                PP_GetInterface_Func local_get_interface,
-                               SyncMessageStatusReceiver* sync_status,
+                               scoped_refptr<IPC::MessageFilter> sync_filter,
                                const PpapiPermissions& permissions)
     : Dispatcher(local_get_interface, permissions),
-      sync_status_(sync_status),
+      sync_filter_(sync_filter),
       pp_module_(module),
       ppb_proxy_(NULL),
       allow_plugin_reentrancy_(false) {
@@ -94,7 +94,7 @@ bool HostDispatcher::InitHostWithChannel(
   if (!Dispatcher::InitWithChannel(delegate, peer_pid, channel_handle,
                                    is_client))
     return false;
-  AddIOThreadMessageFilter(sync_status_.get());
+  AddIOThreadMessageFilter(sync_filter_);
 
   Send(new PpapiMsg_SetPreferences(preferences));
   return true;
@@ -157,9 +157,11 @@ bool HostDispatcher::Send(IPC::Message* msg) {
     // destroys the plugin module and in turn the dispatcher.
     ScopedModuleReference scoped_ref(this);
 
-    sync_status_->BeginBlockOnSyncMessage();
+    FOR_EACH_OBSERVER(SyncMessageStatusObserver, sync_status_observer_list_,
+                      BeginBlockOnSyncMessage());
     bool result = Dispatcher::Send(msg);
-    sync_status_->EndBlockOnSyncMessage();
+    FOR_EACH_OBSERVER(SyncMessageStatusObserver, sync_status_observer_list_,
+                      EndBlockOnSyncMessage());
 
     return result;
   } else {
@@ -240,6 +242,16 @@ const void* HostDispatcher::GetProxiedInterface(const std::string& iface_name) {
   return NULL;
 }
 
+void HostDispatcher::AddSyncMessageStatusObserver(
+    SyncMessageStatusObserver* obs) {
+  sync_status_observer_list_.AddObserver(obs);
+}
+
+void HostDispatcher::RemoveSyncMessageStatusObserver(
+    SyncMessageStatusObserver* obs) {
+  sync_status_observer_list_.RemoveObserver(obs);
+}
+
 void HostDispatcher::AddFilter(IPC::Listener* listener) {
   filters_.push_back(listener);
 }