Add --check-browser flag for browser functionality testing

[raymyers]

Summary

This PR adds a simple command line flag --check-browser to the OpenHands Agent Server that tests browser functionality by attempting to render about:blank. This is meant to make issues like #1327 easier to catch.

Changes

• Added --check-browser command line flag to openhands-agent-server/__main__.py
• Implements browser functionality test that:
  • Registers browser tools
  • Creates a BrowserToolExecutor in headless mode
  • Attempts to navigate to about:blank
  • Returns appropriate exit codes (0 for success, 1 for failure)
  • Provides clear error messages on failure

Usage

# Test browser functionality
python -m openhands.agent_server --check-browser

# Use in deployment scripts
if python -m openhands.agent_server --check-browser; then
    echo "Browser functionality OK"
else
    echo "Browser functionality FAILED"
    exit 1
fi

# Docker health check
HEALTHCHECK CMD python -m openhands.agent_server --check-browser

[raymyers]

/usr/local/bin/openhands-agent-server --check-browse

# ...
INFO     [bubus] 🗣️ EventBus_a4e1b38e🟢(⏳ 1 | ▶️ 1 | ✅ 15 ➡️ 31 👂).dispatch(BrowserStoppedEvent) ➡️ BrowserStoppedEvent#fce1 (#1 pending)
Browser check passed: Successfully rendered about:blank

Exits with 0.

sudo rm /usr/bin/chromium
/usr/local/bin/openhands-agent-server --check-browser
Browser check failed: Chromium is required for browser operations but is not installed.

To install Chromium, run one of the following commands:
  1. Using uvx (recommended): uvx playwright install chromium --with-deps --no-shell
  2. Using pip: pip install playwright && playwright install chromium
  3. Using system package manager:
     - Ubuntu/Debian: sudo apt install chromium-browser
     - macOS: brew install chromium
     - Windows: winget install Chromium.Chromium

After installation, restart your application to use the browser tool.
litellm/llms/custom_httpx/async_client_cleanup.py:66: DeprecationWarning: There is no current event loop

exits with 1