Pepper: Add a test for PPB_TCPSocket_Private.

ppapi/cpp/private/flash_tcp_socket.h

 // Copyright (c) 2011 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.
 
-// TODO(yzshen): This (and the .cc file) contain C++ wrappers for things
-// in ppapi/c/private/ppb_flash_tcp_socket.h. This is currently not used in
-// (or even compiled with) Chromium.
-
 #ifndef PPAPI_CPP_PRIVATE_FLASH_TCP_SOCKET_H_
 #define PPAPI_CPP_PRIVATE_FLASH_TCP_SOCKET_H_
 
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/private/ppb_flash_tcp_socket.h"
 #include "ppapi/cpp/resource.h"
 
 namespace pp {
 
 class CompletionCallback;
 class Instance;
 
 namespace flash {
 
 class TCPSocket : public Resource {
  public:
   explicit TCPSocket(Instance* instance);
 
+  // Returns true if the required interface is available.
+  static bool IsAvailable();
+
   int32_t Connect(const char* host,
                   uint16_t port,
                   const CompletionCallback& callback);
   int32_t ConnectWithNetAddress(const PP_NetAddress_Private* addr,
                                 const CompletionCallback& callback);
   bool GetLocalAddress(PP_NetAddress_Private* local_addr);
   bool GetRemoteAddress(PP_NetAddress_Private* remote_addr);
   int32_t SSLHandshake(const char* server_name,
                        uint16_t server_port,
                        const CompletionCallback& callback);
   int32_t Read(char* buffer,
                int32_t bytes_to_read,
                const CompletionCallback& callback);
   int32_t Write(const char* buffer,
                 int32_t bytes_to_write,
                 const CompletionCallback& callback);
   void Disconnect();
 };
 
 }  // namespace flash
 }  // namespace pp
 
 #endif  // PPAPI_CPP_PRIVATE_FLASH_TCP_SOCKET_H_