Get rid of some downcasts

runtime/bin/process.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/dartutils.h"
 #include "bin/io_buffer.h"
 #include "bin/process.h"
 #include "bin/socket.h"
 
 #include "include/dart_api.h"
@@ skipping 183 matching lines @@
     if (Dart_IsError(error)) Dart_PropagateError(error);
     Dart_ThrowException(error);
   }
 }
 
 
 void FUNCTION_NAME(Process_Kill)(Dart_NativeArguments args) {
   Dart_Handle process = Dart_GetNativeArgument(args, 1);
   intptr_t pid = -1;
   Process::GetProcessIdNativeField(process, &pid);
-  int signal = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 2));
+  intptr_t signal = DartUtils::GetIntptrValue(Dart_GetNativeArgument(args, 2));
   bool success = Process::Kill(pid, signal);
   Dart_SetReturnValue(args, Dart_NewBoolean(success));
 }
 
 
 void FUNCTION_NAME(Process_Exit)(Dart_NativeArguments args) {
   int64_t status = 0;
   // Ignore result if passing invalid argument and just exit 0.
   DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 0), &status);
   exit(static_cast<int>(status));
@@ skipping 67 matching lines @@
   int external_length = strlen(system_string);
   uint8_t* buffer = NULL;
   Dart_Handle external_array = IOBuffer::Allocate(external_length, &buffer);
   memmove(buffer, system_string, external_length);
   if (utf8 != system_string) free(const_cast<char*>(system_string));
   Dart_SetReturnValue(args, external_array);
 }
 
 }  // namespace bin
 }  // namespace dart