Additional fixes for warning mismatch with scons.

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 "native_client/src/trusted/plugin/nacl_subprocess.h"
 
 #include <stdarg.h>
 
 #include "native_client/src/shared/srpc/nacl_srpc.h"
 #include "native_client/src/trusted/plugin/plugin_error.h"
@@ skipping 85 matching lines @@
         // SrpcParam's destructor *should* free the allocated array
         const char* orig_arr = va_arg(vl, const char*);
         size_t len = va_arg(vl, size_t);
         char* input = (char *)malloc(len);
         if (!input) {
           PLUGIN_PRINTF(("VInvokeSrpcMethod (allocation failure)\n"));
           return false;
         }
         memcpy(input, orig_arr, len);
         params->ins()[i]->arrays.carr = input;
-        params->ins()[i]->u.count = len;
+        params->ins()[i]->u.count = static_cast<nacl_abi_size_t>(len);
         break;
       }
       case NACL_SRPC_ARG_TYPE_HANDLE: {
         NaClSrpcImcDescType input = va_arg(vl, NaClSrpcImcDescType);
         params->ins()[i]->u.hval = input;
         break;
       }
       case NACL_SRPC_ARG_TYPE_INT: {
         int32_t input = va_arg(vl, int32_t);
         params->ins()[i]->u.ival = input;
@@ skipping 14 matching lines @@
         }
         params->ins()[i]->arrays.str = input;
         break;
       }
     }
   }
   return srpc_client_->Invoke(method_name, params);
 }
 
 }  // namespace plugin