Split dart_api.h into multiple parts:

samples/sample_extension/sample_extension.cc

 // Copyright (c) 2012, 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 <string.h>
 #include <stdlib.h>
 #include <stdio.h>
-#include "dart_api.h"
+#include "include/dart_api.h"
+#include "include/dart_native_api.h"
 
 Dart_NativeFunction ResolveName(Dart_Handle name, int argc);
 
 DART_EXPORT Dart_Handle sample_extension_Init(Dart_Handle parent_library) {
   if (Dart_IsError(parent_library)) { return parent_library; }
 
   Dart_Handle result_code = Dart_SetNativeResolver(parent_library, ResolveName);
   if (Dart_IsError(result_code)) return result_code;
 
   return Dart_Null();
@@ skipping 107 matching lines @@
 
   for (int i=0; function_list[i].name != NULL; ++i) {
     if (strcmp(function_list[i].name, cname) == 0) {
       result = function_list[i].function;
       break;
     }
   }
   Dart_ExitScope();
   return result;
 }