UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.101 Safari/537.36

Example URL:

Steps to reproduce the problem:
1. Create file "manifest.json":
{
  "manifest_version": 2,
  "name": "Extension name",
  "version": "0",
  "minimum_chrome_version": "31",
  "background": {
    "persistent": false,
    "scripts": [ "event_page.js" ]
  },
  "permissions": [
    "downloads",
    "https://example.com/*"
  ]
}

2. Create file "event_page.js":
chrome.downloads.onDeterminingFilename.addListener(
  (download_item, suggest) =>
  {
    suggest(
      {
        conflictAction: "uniquify",
        filename: "article_id.html"
      }
    );
  }
);
chrome.downloads.download(
  {
    url: "https://example.com/get.php?q=article_id",
    filename: "article_id.html",
    conflictAction: "uniquify",
    saveAs: false
  }
);

3. Create chrome extension.
4. Extension will send request to server "example.com".
5. Server will send response to browser with header like:
Content-Disposition; attachment; filename="article_id.html"; filename*=UTF-8''extremely%20long%20localized%20file%20name%20based%20on%20article%20title.html
Length of server proposed UTF-8 file name in bytes larger then file system path length limit.

What is the expected behavior?
If there are extension proposed file name ("filename"), never use server proposed file name and try to use extension proposed "filename"; if "saveAs:true", show dialog "Save as", pre-populated with the extension proposed "filename"; if "saveAs:false", do not show dialog; if "conflictAction" specified, use it (auto rename, overwrite or show "Save as" dialog, pre-populated with the extension proposed "filename"); if previously steps failed, show "Save as" dialog.

What went wrong?
"Save as" dialog displayed for each request (short "filename", "saveAs:false" and "conflictAction" always ignored). Extension's function "chrome.downloads.download()" and handler of event "chrome.downloads.onDeterminingFilename" can not rename file.

Did this work before? N/A 

Chrome version: 60.0.3112.101  Channel: stable
OS Version: Ubuntu 16.04
Flash Version: