Complete SyncMessageFilter initialization after SyncChannel initialization

ipc/ipc_sync_channel.cc

Index: ipc/ipc_sync_channel.cc
diff --git a/ipc/ipc_sync_channel.cc b/ipc/ipc_sync_channel.cc
index 845eccd813d2f408d8da76ce4aeddd5ce5e2a56b..04ebd4177ef857c466c8fb85c994f6a1facc2c5a 100644
--- a/ipc/ipc_sync_channel.cc
+++ b/ipc/ipc_sync_channel.cc
@@ -465,6 +465,8 @@ scoped_refptr<SyncMessageFilter> SyncChannel::CreateSyncMessageFilter() {
       sync_context()->shutdown_event(),
       sync_context()->IsChannelSendThreadSafe());
   AddFilter(filter.get());
+  if (!did_init())
+    pre_init_sync_message_filters_.push_back(filter);
   return filter;
 }
 
@@ -592,4 +594,12 @@ void SyncChannel::StartWatching() {
                                   dispatch_watcher_callback_);
 }
 
+void SyncChannel::OnChannelInit() {
+  for (const auto& filter : pre_init_sync_message_filters_) {
+    filter->set_is_channel_send_thread_safe(
+        context()->IsChannelSendThreadSafe());
+  }
+  pre_init_sync_message_filters_.clear();
+}
+
 }  // namespace IPC