[Bug]: Download event's saveAs fails with chromium connected over the CDP

[vvzz]

Version

1.49.0

Steps to reproduce

I'm running playwright in a container that is connecting to the Chrome started on the host machine like so:
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --remote-debugging-port=9222 --user-data-dir=/tmp/chrome-debug --remote-allow-origins="*"

I'm connecting to it from playwright roughly like so:

const { chromium } = require('playwright');

(async () => {
    const browser = await chromium.connectOverCDP('ws://host.docker.internal:9222/devtools/browser/24923805-d4d0-48de-805c-bae17bd4c386');
    const context = browser.contexts()[0] || await browser.newContext();
    const page = context.pages()[0] || await context.newPage();

    // Listen for download event
    page.on('download', async (download) => {
        const path = await download.path();
        const suggestedFilename = download.suggestedFilename();
        
        await download.saveAs("/tmp/workspaces/file.pdf");
        console.log(`Downloaded file saved as: ${savePath}`);
    });

    console.log('Connected to Chrome via CDP');


    await page.goto('https://some-test.site');
    await page.click("#downloadLink")



})();

Expected behavior

Should save the file to "/tmp/workspaces/file.pdf on the machine running playwright.

Actual behavior

An exception happens.

Error: download.saveAs: ENOENT: no such file or directory, copyfile '/tmp/playwright-artifacts-MedLPD/537add71-ff6a-4dfa-85e7-f6f2f68080f8'

Same thing happens when trying to use the stream.

After further investigation, it looks like it tries to copy the file locally(on the machine running playwright) instead of getting the file over the CDP protocol.

Additional context

Environment

System:
    OS: Linux 6.10 Debian GNU/Linux 11 (bullseye) 11 (bullseye)
    CPU: (14) arm64 unknown
    Memory: 20.96 GB / 31.29 GB
    Container: Yes
  Binaries:
    Node: 18.19.0 - /usr/local/bin/node
    Yarn: 4.0.1 - /usr/local/bin/yarn
    npm: 10.2.3 - /usr/local/bin/npm
    pnpm: 8.15.1 - /usr/local/share/npm-global/bin/pnpm
  IDEs:
    VSCode: 1.96.4 - /vscode/vscode-server/bin/linux-arm64/cd4ee3b1c348a13bafd8f9ad8060705f6d4b9cba/bin/remote-cli/code
  Languages:
    Bash: 5.1.4 - /bin/bash

[vvzz]

Also this seems like it could be potentially related to #15999

[agg23]

Some functionality doesn't function using CDP. You should instead use Playwright's communication protocol using connect().

[oscar-o-oneill]

Oh man, not planned? I'm using CDP at the moment but this limitation really sucks...