[mojo-edk] Add MojoWatch and MojoCancelWatch APIs

mojo/edk/system/shared_buffer_dispatcher.h

Index: mojo/edk/system/shared_buffer_dispatcher.h
diff --git a/mojo/edk/system/shared_buffer_dispatcher.h b/mojo/edk/system/shared_buffer_dispatcher.h
index a8d5bcda14861d8e6fd3ac4663e1d58ec2df6cd2..1770b7b0fcf4909174a54ce3895ff806954b48ec 100644
--- a/mojo/edk/system/shared_buffer_dispatcher.h
+++ b/mojo/edk/system/shared_buffer_dispatcher.h
@@ -67,7 +67,7 @@ class MOJO_SYSTEM_IMPL_EXPORT SharedBufferDispatcher final : public Dispatcher {
 
   // Dispatcher:
   Type GetType() const override;
-  MojoResult Close() override;
+  MojoResult Close(RequestContext* request_context) override;
   MojoResult DuplicateBufferHandle(
       const MojoDuplicateBufferHandleOptions* options,
       scoped_refptr<Dispatcher>* new_dispatcher) override;
@@ -82,9 +82,9 @@ class MOJO_SYSTEM_IMPL_EXPORT SharedBufferDispatcher final : public Dispatcher {
   bool EndSerialize(void* destination,
                     ports::PortName* ports,
                     PlatformHandle* handles) override;
-  bool BeginTransit() override;
-  void CompleteTransitAndClose() override;
-  void CancelTransit() override;
+  bool BeginTransit(RequestContext* request_context) override;
+  void CompleteTransitAndClose(RequestContext* request_context) override;
+  void CancelTransit(RequestContext* request_context) override;
 
  private:
   static scoped_refptr<SharedBufferDispatcher> CreateInternal(