Mojo EDK: Introduce MojoQueryHandleSignalsState API

mojo/edk/system/core.cc

Index: mojo/edk/system/core.cc
diff --git a/mojo/edk/system/core.cc b/mojo/edk/system/core.cc
index cfe01fabb156654f01d0bd5ee5b05be09f2e2db1..263f9cd6f859a4dacbabafd802dca0340bf7d35c 100644
--- a/mojo/edk/system/core.cc
+++ b/mojo/edk/system/core.cc
@@ -378,6 +378,17 @@ MojoResult Core::Close(MojoHandle handle) {
   return MOJO_RESULT_OK;
 }
 
+MojoResult Core::QueryHandleSignalsState(
+    MojoHandle handle,
+    MojoHandleSignalsState* signals_state) {
+  RequestContext request_context;
+  scoped_refptr<Dispatcher> dispatcher = GetDispatcher(handle);
+  if (!dispatcher || !signals_state)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+  *signals_state = dispatcher->GetHandleSignalsState();
+  return MOJO_RESULT_OK;
+}
+
 MojoResult Core::Wait(MojoHandle handle,
                       MojoHandleSignals signals,
                       MojoDeadline deadline,