[DO NOT REVIEW][DO NOT COMMIT] Introduce WebDataProducerHandle.

public/platform/WebDataConsumerHandle.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 WebDataConsumerHandle_h
 #define WebDataConsumerHandle_h
 
 #include <stddef.h>
+#include <stdint.h>
 
 namespace blink {
 
 // WebDataConsumerHandle represents the "consumer" side of a data pipe. A user
 // can read data from it.
 // This data type is basically a wrapper of mojo data pipe consumer handle.
 // See mojo/public/c/system/data_pipe.h for details.
 //
 // Note:
 //  - If you register a client, all of read / beginRead / endRead /
 //    registerClient / unregisterClient must be called on the same thread.
 //    Client notification is called on the thread.
 class WebDataConsumerHandle {
 public:
     // This corresponds to MojoReadDataFlags.
-    using Flags = unsigned;
+    using Flags = uint32_t;
     static const Flags FlagNone = 0;
 
     enum Result {
         Ok,
         Done,
         Busy,
         ShouldWait,
         ResourceExhausted,
         UnexpectedError,
     };
@@ skipping 30 matching lines @@
     // Only one registration can be made for a handle at a time.
     virtual void registerClient(Client* /* client */)  { }
 
     // Unregisters |client| from this handle.
     virtual void unregisterClient() { }
 };
 
 } // namespace blink
 
 #endif // WebDataConsumerHandle_h