Refactor the dart api a bit:

runtime/bin/builtin_in.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 <assert.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "include/dart_api.h"
 
@@ skipping 48 matching lines @@
   const char* name_;
   Dart_NativeFunction function_;
   int argument_count_;
 } BuiltinEntries[] = {
   BUILTIN_NATIVE_LIST(REGISTER_FUNCTION)
 };
 
 
 static Dart_NativeFunction native_lookup(Dart_Handle name,
                                          int argument_count) {
-  Dart_Result result = Dart_StringToCString(name);
-  assert(Dart_IsValidResult(result));
-  const char* function_name = Dart_GetResultAsCString(result);
-  assert(function_name != NULL);
+  const char* function_name = NULL;
+  Dart_Handle result = Dart_StringToCString(name, &function_name);
+  ASSERT(Dart_IsValid(result));
+  ASSERT(function_name != NULL);
   int num_entries = sizeof(BuiltinEntries) / sizeof(struct NativeEntries);
   for (int i = 0; i < num_entries; i++) {
     struct NativeEntries* entry = &(BuiltinEntries[i]);
     if (!strcmp(function_name, entry->name_)) {
       if (entry->argument_count_ == argument_count) {
         return reinterpret_cast<Dart_NativeFunction>(entry->function_);
       } else {
         // Wrong number of arguments.
         // TODO(regis): Should we pass a buffer for error reporting?
         return NULL;
       }
     }
   }
   return NULL;
 }
 
 
 void Builtin_LoadLibrary() {
   Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
-  Dart_Result result = Dart_LookupLibrary(url);
-  if (Dart_IsValidResult(result)) {
+  Dart_Handle result = Dart_LookupLibrary(url);
+  if (Dart_IsValid(result)) {
     // Builtin library already loaded.
     return;
   }
 
   // Load the library.
   Dart_Handle source = Dart_NewString(Builtin_source_);
-  result = Dart_LoadLibrary(url, source);
-  assert(Dart_IsValidResult(result));
-  Dart_Handle builtin_lib = Dart_GetResult(result);
+  Dart_Handle builtin_lib = Dart_LoadLibrary(url, source);
+  ASSERT(Dart_IsValid(builtin_lib));
 
   // Lookup the core libraries and inject the builtin library into them.
-  result = Dart_LookupLibrary(Dart_NewString("dart:core"));
-  assert(Dart_IsValidResult(result));
-  Dart_Handle core_lib = Dart_GetResult(result);
+  Dart_Handle core_lib = Dart_LookupLibrary(Dart_NewString("dart:core"));
+  ASSERT(Dart_IsValid(core_lib));
   result = Dart_LibraryImportLibrary(core_lib, builtin_lib);
-  assert(Dart_IsValidResult(result));
+  ASSERT(Dart_IsValid(result));
 
-  result = Dart_LookupLibrary(Dart_NewString("dart:coreimpl"));
-  assert(Dart_IsValidResult(result));
-  Dart_Handle coreimpl_lib = Dart_GetResult(result);
+  Dart_Handle coreimpl_lib =
+      Dart_LookupLibrary(Dart_NewString("dart:coreimpl"));
+  ASSERT(Dart_IsValid(coreimpl_lib));
   result = Dart_LibraryImportLibrary(coreimpl_lib, builtin_lib);
-  assert(Dart_IsValidResult(result));
+  ASSERT(Dart_IsValid(result));
   result = Dart_LibraryImportLibrary(builtin_lib, coreimpl_lib);
-  assert(Dart_IsValidResult(result));
+  ASSERT(Dart_IsValid(result));
 
   // Create a native wrapper "FileNativeWrapper" so that we can add a
   // native field to store the OS file handle for implementing all the
   // file operations. The class "File" extends "FileNativeWrapper".
   Dart_Handle name = Dart_NewString("FileNativeWrapper");
   const int kNumFileFields = 1;
   result = Dart_CreateNativeWrapperClass(builtin_lib, name, kNumFileFields);
-  assert(Dart_IsValidResult(result));
+  ASSERT(Dart_IsValid(result));
 
   // Create a native wrapper "EventHandlerNativeWrapper" so that we can add a
   // native field to store the event handle for implementing all
   // event operations.
   name = Dart_NewString("EventHandlerNativeWrapper");
   const int kNumEventHandlerFields = 1;
   result = Dart_CreateNativeWrapperClass(builtin_lib,
                                          name,
                                          kNumEventHandlerFields);
-  assert(Dart_IsValidResult(result));
+  ASSERT(Dart_IsValid(result));
 }
 
 
 void Builtin_ImportLibrary(Dart_Handle library) {
   Builtin_LoadLibrary();
 
   Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
-  Dart_Result result = Dart_LookupLibrary(url);
-  assert(Dart_IsValidResult(result));
-  Dart_Handle builtin_lib = Dart_GetResult(result);
-  result = Dart_LibraryImportLibrary(library, builtin_lib);
-  assert(Dart_IsValidResult(result));
+  Dart_Handle builtin_lib = Dart_LookupLibrary(url);
+  ASSERT(Dart_IsValid(builtin_lib));
+  Dart_Handle result = Dart_LibraryImportLibrary(library, builtin_lib);
+  ASSERT(Dart_IsValid(result));
 }
 
 
 void Builtin_SetNativeResolver() {
   Dart_Handle url = Dart_NewString(DartUtils::kBuiltinLibURL);
-  Dart_Result result = Dart_LookupLibrary(url);
-  assert(Dart_IsValidResult(result));
-  Dart_Handle builtin_lib = Dart_GetResult(result);
-  result = Dart_SetNativeResolver(builtin_lib, native_lookup);
-  assert(Dart_IsValidResult(result));
+  Dart_Handle builtin_lib = Dart_LookupLibrary(url);
+  ASSERT(Dart_IsValid(builtin_lib));
+  Dart_Handle result = Dart_SetNativeResolver(builtin_lib, native_lookup);
+  ASSERT(Dart_IsValid(result));
 }