Allow Dart_Null to be passed in for the import map in Dart_LoadLibrary and Dart_LoadScript.

vm/dart_api_impl_test.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 "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_state.h"
@@ skipping 2781 matching lines @@
   EXPECT_STREQ("Dart_LookupLibrary: library 'noodles.dart' not found.",
                Dart_GetError(result));
 }
 
 
 TEST_CASE(LibraryUrl) {
   const char* kLibrary1Chars =
       "#library('library1_name');";
   Dart_Handle url = Dart_NewString("library1_url");
   Dart_Handle source = Dart_NewString(kLibrary1Chars);
-  Dart_Handle import_map = Dart_NewList(0);
-  Dart_Handle lib = Dart_LoadLibrary(url, source, import_map);
+  Dart_Handle lib = Dart_LoadLibrary(url, source, Dart_Null());
   Dart_Handle error = Dart_Error("incoming error");
   EXPECT_VALID(lib);
 
   Dart_Handle result = Dart_LibraryUrl(Dart_Null());
   EXPECT(Dart_IsError(result));
   EXPECT_STREQ("Dart_LibraryUrl expects argument 'library' to be non-null.",
                Dart_GetError(result));
 
   result = Dart_LibraryUrl(Dart_True());
   EXPECT(Dart_IsError(result));
@@ skipping 353 matching lines @@
       "#library('library1.dart');"
       "#import('library2.dart');"
       "var foo1;";
   const char* kLibrary2Chars =
       "#library('library2.dart');"
       "var foo;";
   Dart_Handle result;
   // Create a test library and Load up a test script in it.
   Dart_Handle url = Dart_NewString(TestCase::url());
   Dart_Handle source = Dart_NewString(kScriptChars);
-  Dart_Handle import_map = Dart_NewList(0);
-  result = Dart_LoadScript(url, source, library_handler, import_map);
+  result = Dart_LoadScript(url, source, library_handler, Dart_Null());
 
   url = Dart_NewString("library1.dart");
   source = Dart_NewString(kLibrary1Chars);
-  Dart_LoadLibrary(url, source, import_map);
+  Dart_LoadLibrary(url, source, Dart_Null());
 
   url = Dart_NewString("library2.dart");
   source = Dart_NewString(kLibrary2Chars);
-  Dart_LoadLibrary(url, source, import_map);
+  Dart_LoadLibrary(url, source, Dart_Null());
 
   result = Dart_InvokeStatic(result,
                              Dart_NewString(""),
                              Dart_NewString("main"),
                              0,
                              NULL);
   EXPECT(Dart_IsError(result));
   EXPECT_STREQ("Duplicate definition : 'foo' is defined in"
                " 'library2.dart' and 'dart:test-lib'\n",
                Dart_GetError(result));
@@ skipping 536 matching lines @@
   // We should have received the expected number of interrupts.
   EXPECT_EQ(kInterruptCount, interrupt_count);
 
   // Give the spawned thread enough time to properly exit.
   Isolate::SetInterruptCallback(saved);
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart