ppapi: PPB_VpnProvider: Define API

ppapi/shared_impl/vpn_provider_util.h

+// Copyright 2016 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 PPAPI_SHAERD_IMPL_VPN_PROVIDER_UTIL_H_
+#define PPAPI_SHAERD_IMPL_VPN_PROVIDER_UTIL_H_
+
+#include "base/memory/shared_memory.h"
+
+namespace ppapi {
+
+class VpnProviderSharedBuffer {
+ public:
+  VpnProviderSharedBuffer(uint32_t capacity,
+                          uint32_t packet_size,
+                          std::unique_ptr<base::SharedMemory> shm);
+  ~VpnProviderSharedBuffer();
+
+  bool GetAvailable(uint32_t* id);
+  void SetAvailable(uint32_t id, bool value);
+  void* GetBuffer(uint32_t id);
+  base::SharedMemoryHandle GetHandle();
+
+ private:
+  uint32_t capacity_;
+  uint32_t packet_size_;
+  std::unique_ptr<base::SharedMemory> shm_;
+  std::unique_ptr<bool[]> available_;
+};
+
+}  // namespace ppapi
+
+#endif  // PPAPI_SHAERD_IMPL_VPN_PROVIDER_UTIL_H_