NaCl: Remove now-unneeded SRPC reverse service code

ppapi/native_client/src/trusted/plugin/nacl_subprocess.cc

 // Copyright (c) 2012 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.
 
 #include "ppapi/native_client/src/trusted/plugin/nacl_subprocess.h"
 
 #include <stdarg.h>
 
+#include <sstream>
+
 #include "native_client/src/shared/srpc/nacl_srpc.h"
 #include "ppapi/native_client/src/trusted/plugin/plugin_error.h"
 #include "ppapi/native_client/src/trusted/plugin/srpc_params.h"
 
 namespace plugin {
 
 std::string NaClSubprocess::detailed_description() const {
   std::stringstream ss;
   ss << description()
      << "={ this=" << static_cast<const void*>(this)
@@ skipping 108 matching lines @@
         }
         params->ins()[i]->arrays.str = input;
         break;
       }
     }
   }
   return srpc_client_->Invoke(method_name, params);
 }
 
 }  // namespace plugin