Refactor the dart api a bit:

runtime/bin/process.cc

 // Copyright (c) 2011, 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/process.h"
 
 #include "include/dart_api.h"
 
 void FUNCTION_NAME(Process_Start)(Dart_NativeArguments args) {
   Dart_EnterScope();
   Dart_Handle process =  Dart_GetNativeArgument(args, 0);
   intptr_t in;
   intptr_t out;
   intptr_t err;
   intptr_t exit_event;
   const char* path =
       DartUtils::GetStringValue(Dart_GetNativeArgument(args, 1));
   Dart_Handle arguments = Dart_GetNativeArgument(args, 2);
   ASSERT(Dart_IsArray(arguments));
-  Dart_Result result = Dart_GetLength(arguments);
-  ASSERT(Dart_IsValidResult(result));
-  intptr_t length = Dart_GetResultAsCIntptr(result);
+  intptr_t length = 0;
+  Dart_Handle result = Dart_GetLength(arguments, &length);
+  ASSERT(Dart_IsValid(result));
   char** string_args = new char*[length];
   for (int i = 0; i < length; i++) {
-    result = Dart_ArrayGetAt(arguments, i);
-    ASSERT(Dart_IsValidResult(result));
-    Dart_Handle arg = Dart_GetResult(result);
+    Dart_Handle arg = Dart_ArrayGetAt(arguments, i);
+    ASSERT(Dart_IsValid(arg));
     string_args[i] = const_cast<char *>(DartUtils::GetStringValue(arg));
   }
   Dart_Handle in_handle = Dart_GetNativeArgument(args, 3);
   Dart_Handle out_handle = Dart_GetNativeArgument(args, 4);
   Dart_Handle err_handle = Dart_GetNativeArgument(args, 5);
   Dart_Handle exit_handle = Dart_GetNativeArgument(args, 6);
   Dart_Handle status_handle = Dart_GetNativeArgument(args, 7);
   intptr_t pid = -1;
   static const int kMaxChildOsErrorMessageLength = 256;
   char os_error_message[kMaxChildOsErrorMessageLength];
@@ skipping 31 matching lines @@
   Dart_ExitScope();
 }
 
 
 void FUNCTION_NAME(Process_Exit)(Dart_NativeArguments args) {
   Dart_EnterScope();
   intptr_t pid = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 1));
   Process::Exit(pid);
   Dart_ExitScope();
 }