Plumb the handle signals state out of Waiter::Wait().

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 f762c8cc482f91f2e9d6587e743d395384aa02b7..c8658a86aec584e72cfe733fa3d7c269da5771c5 100644
--- a/mojo/edk/system/core.cc
+++ b/mojo/edk/system/core.cc
@@ -803,7 +803,7 @@ MojoResult Core::WaitManyInternal(const MojoHandle* handles,
   if (result == MOJO_RESULT_ALREADY_EXISTS)
     result = MOJO_RESULT_OK;  // The i-th one is already "triggered".
   else if (result == MOJO_RESULT_OK)
-    result = waiter.Wait(deadline, result_index);
+    result = waiter.Wait(deadline, result_index, nullptr);
 
   // Make sure no other dispatchers try to wake |waiter| for the current
   // |Wait()|/|WaitMany()| call. (Only after doing this can |waiter| be