Fix compilation errors on Linux.

atom/browser/ui/gtk/app_indicator_icon.cc

@@ -137,13 +137,12 @@ base::FilePath CreateTempImageFile(gfx::ImageSkia* image_ptr,
   // Create a new temporary directory for each image since using a single
   // temporary directory seems to have issues when changing icons in quick
   // succession.
-  if (!file_util::CreateNewTempDirectory(base::FilePath::StringType(),
-                                         &temp_dir))
+  if (!base::CreateNewTempDirectory(base::FilePath::StringType(), &temp_dir))
     return base::FilePath();
   new_file_path =
       temp_dir.Append(id + base::StringPrintf("_%d.png", icon_change_count));
   int bytes_written =
-      file_util::WriteFile(
+      base::WriteFile(
           new_file_path,
           reinterpret_cast<const char*>(png_data->front()),
           png_data->size());