Send input event IPCs directly from the UI thread

ipc/ipc_sync_message_filter.cc

Index: ipc/ipc_sync_message_filter.cc
diff --git a/ipc/ipc_sync_message_filter.cc b/ipc/ipc_sync_message_filter.cc
index da883f6fd6876d45cb01af08453cc8f76944b970..6504aee7ceb42fd9c557ccf805c31820d820340e 100644
--- a/ipc/ipc_sync_message_filter.cc
+++ b/ipc/ipc_sync_message_filter.cc
@@ -19,10 +19,7 @@ bool SyncMessageFilter::Send(Message* message) {
   if (!message->is_sync()) {
     {
       base::AutoLock auto_lock(lock_);
-      if (sender_ && is_channel_send_thread_safe_) {
-        sender_->Send(message);
-        return true;
-      } else if (!io_task_runner_.get()) {
+      if (!io_task_runner_.get()) {
         pending_messages_.push_back(message);
         return true;
       }
@@ -117,6 +114,19 @@ bool SyncMessageFilter::OnMessageReceived(const Message& message) {
   return false;
 }
 
+bool SyncMessageFilter::SendNow(std::unique_ptr<Message> message) {
+  if (!message->is_sync()) {
+    base::AutoLock auto_lock(lock_);
+    if (sender_ && is_channel_send_thread_safe_) {
+      sender_->Send(message.release());
+      return true;
+    }
+  }
+
+  // Fall back on default Send behavior.
+  return Send(message.release());
+}
+
 SyncMessageFilter::SyncMessageFilter(base::WaitableEvent* shutdown_event,
                                      bool is_channel_send_thread_safe)
     : sender_(NULL),