loadFile method
Loads the file located on the specified absoluteFilePath.
The absoluteFilePath parameter should contain the absolute path to the
file as it is stored on the device. For example:
/Users/username/Documents/www/index.html.
Throws an ArgumentError if the absoluteFilePath does not exist.
Implementation
@override
Future<void> loadFile(String absoluteFilePath) {
return controller.loadRequest_(absoluteFilePath);
}