1、打开https://www.browserscan.net/zh/

2、将internal-pdf-viewer改为 internal-pdf-viewer-jdtest看下效果：

3、源码修改：

 third_party\blink\renderer\modules\plugins\dom_plugin_array.cc

namespace {
DOMPlugin* MakeFakePlugin(String plugin_name, LocalDOMWindow* window) {
  String description = "Portable Document Format";
  String filename = "internal-pdf-viewer-jdtest";
  auto* plugin_info =
      MakeGarbageCollected<PluginInfo>(plugin_name, filename, description,
                                       /*background_color=*/Color::kTransparent,
                                       /*may_use_external_handler=*/false);
  Vector<String> extensions{"pdf"};
  for (const char* mime_type : {"application/pdf", "text/pdf"}) {
    auto* mime_info = MakeGarbageCollected<MimeClassInfo>(
        mime_type, description, *plugin_info, extensions);
    plugin_info->AddMimeType(mime_info);
  }
  return MakeGarbageCollected<DOMPlugin>(window, *plugin_info);
}
}  // namespace

修改下String filename = "internal-pdf-viewer-jdtest";名字即可。