[mojo-edk] Add MojoWatch and MojoCancelWatch APIs

mojo/edk/system/handle_table.h

Index: mojo/edk/system/handle_table.h
diff --git a/mojo/edk/system/handle_table.h b/mojo/edk/system/handle_table.h
index ecfb21e0659690fbc717bc778fc9bee84db2cb74..739857d47b0b136daac02d77f1fc7d05020d6c04 100644
--- a/mojo/edk/system/handle_table.h
+++ b/mojo/edk/system/handle_table.h
@@ -40,12 +40,16 @@ class HandleTable {
   MojoResult BeginTransit(
       const MojoHandle* handles,
       uint32_t num_handles,
-      std::vector<Dispatcher::DispatcherInTransit>* dispatchers);
+      std::vector<Dispatcher::DispatcherInTransit>* dispatchers,
+      Dispatcher::RequestContext* request_context);
 
   void CompleteTransitAndClose(
-      const std::vector<Dispatcher::DispatcherInTransit>& dispatchers);
+      const std::vector<Dispatcher::DispatcherInTransit>& dispatchers,
+      Dispatcher::RequestContext* request_context);
+
   void CancelTransit(
-      const std::vector<Dispatcher::DispatcherInTransit>& dispatchers);
+      const std::vector<Dispatcher::DispatcherInTransit>& dispatchers,
+      Dispatcher::RequestContext* request_context);
 
   void GetActiveHandlesForTest(std::vector<MojoHandle> *handles);