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

public/platform/WebCreateDataPipeOptions.h

+// Copyright 2015 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 WebCreateDataPipeOptions_h
+#define WebCreateDataPipeOptions_h
+
+#include <stdint.h>
+
+namespace blink {
+
+class WebCreateDataPipeOptions {
+public:
+    using Flags = uint32_t;
+    static const Flags FlagNone = 0;
+    static const Flags FlagMayDiscard = 1;
+
+    WebCreateDataPipeOptions(Flags flags, uint32_t elementNumBytes, uint32_t capacityNumBytes)
+        : flags(flags), elementNumBytes(elementNumBytes), capacityNumBytes(capacityNumBytes) { }
+
+    Flags flags;
+    uint32_t elementNumBytes;
+    uint32_t capacityNumBytes;
+};
+
+} // namespace blink
+
+#endif // WebCreateDataPipeOptions_h