Make Dispatcher::Type an enum class.

mojo/edk/system/transport_data.h

Index: mojo/edk/system/transport_data.h
diff --git a/mojo/edk/system/transport_data.h b/mojo/edk/system/transport_data.h
index 9911b110d0cae4088c8b5617286d3b201081679a..7cb25d3bb98dfbaec3ebe3dfdb8939ce98f8d114 100644
--- a/mojo/edk/system/transport_data.h
+++ b/mojo/edk/system/transport_data.h
@@ -162,7 +162,8 @@ class MOJO_SYSTEM_IMPL_EXPORT TransportData {
   };
 
   struct HandleTableEntry {
-    int32_t type;     // From |Dispatcher::Type| (|kTypeUnknown| for "invalid").
+    // TODO(vtl): Should I make |Dispatcher::Type| an |int32_t| enum class?

[yzshen1, 2015/06/01 15:48:17]

I wonder what are the reasons not to make it sized?

+    int32_t type;     // From |Dispatcher::Type| (|UNKNOWN| for "invalid").
     uint32_t offset;  // Relative to the start of the "secondary buffer".
     uint32_t size;    // (Not including any padding.)
     uint32_t unused;