More fixes.

runtime/vm/dart_api_impl.cc

Index: runtime/vm/dart_api_impl.cc
diff --git a/runtime/vm/dart_api_impl.cc b/runtime/vm/dart_api_impl.cc
index 4fd30032a592101eacb0fc33941c87590b484cb0..1e8dcc06ebb6fb67084de24ec4e0ae5d425ab84e 100644
--- a/runtime/vm/dart_api_impl.cc
+++ b/runtime/vm/dart_api_impl.cc
@@ -5518,7 +5518,7 @@ DART_EXPORT Dart_Handle Dart_LoadLibrary(Dart_Handle url,
   if (url_str.IsNull()) {
     RETURN_TYPE_ERROR(Z, url, String);
   }
-  if (Dart_IsNull(resolved_url)) {
+  if (::Dart_IsNull(resolved_url)) {
     resolved_url = url;
   }
   const String& resolved_url_str = Api::UnwrapStringHandle(Z, resolved_url);
@@ -5637,7 +5637,7 @@ DART_EXPORT Dart_Handle Dart_LoadSource(Dart_Handle library,
   if (url_str.IsNull()) {
     RETURN_TYPE_ERROR(Z, url, String);
   }
-  if (Dart_IsNull(resolved_url)) {
+  if (::Dart_IsNull(resolved_url)) {
     resolved_url = url;
   }
   const String& resolved_url_str = Api::UnwrapStringHandle(Z, resolved_url);