Make Dispatcher::Type an enum class.

mojo/edk/system/transport_data.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_EDK_SYSTEM_TRANSPORT_DATA_H_
 #define MOJO_EDK_SYSTEM_TRANSPORT_DATA_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 144 matching lines @@
   // |MessageInTransit::kMessageAlignment| in size. Must be POD.
   struct Header {
     uint32_t num_handles;
     // TODO(vtl): Not used yet:
     uint32_t platform_handle_table_offset;
     uint32_t num_platform_handles;
     uint32_t unused;
   };
 
   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;
   };
 
   const Header* header() const {
     return reinterpret_cast<const Header*>(buffer_.get());
   }
 
   size_t buffer_size_;
   scoped_ptr<char, base::AlignedFreeDeleter> buffer_;  // Never null.
 
   // Any platform-specific handles attached to this message (for inter-process
   // transport). The vector (if any) owns the handles that it contains (and is
   // responsible for closing them).
   // TODO(vtl): With C++11, change it to a vector of |ScopedPlatformHandle|s.
   embedder::ScopedPlatformHandleVectorPtr platform_handles_;
 
   DISALLOW_COPY_AND_ASSIGN(TransportData);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_TRANSPORT_DATA_H_