Steps to reproduce the problem:
There is no easy way to repro the issue, it requires custom code mods. However, the bug is obvious: ChromeHttpAuthHandler attempts to create LoginPrompt even when activity == null.

What is the expected behavior?
Shouldn't crash

What went wrong?
java/org/chromium/chrome/browser/ChromeHttpAuthHandler.java, method showDialog (https://cs.chromium.org/chromium/src/chrome/android/java/src/org/chromium/chrome/browser/ChromeHttpAuthHandler.java?q=ChromeHttpAuthHandler&sq=package:chromium&dr=CSs&l=21)

    @CalledByNative
    private void showDialog(WindowAndroid windowAndroid) {
        if (windowAndroid == null) {
            cancel();
        }
        Activity activity = windowAndroid.getActivity().get();
        if (activity == null) {
            cancel();
        }
//!!! LoginPrompt is still being created even if activity == null !!!
        LoginPrompt authDialog = new LoginPrompt(activity, this);
        setAutofillObserver(authDialog);
        authDialog.show();
    }

It crashes inside the LoginPrompt where the null activity is used to get the dialog layout. I guess, the fix should be like that:

    @CalledByNative
    private void showDialog(WindowAndroid windowAndroid) {
        if (windowAndroid == null) {
            cancel();
        }
        Activity activity = windowAndroid.getActivity().get();
        if (activity == null) {
            cancel();
        }
        else { //!AB, do not try to create LoginPrompt with the null activity.
            LoginPrompt authDialog = new LoginPrompt(activity, this);
            setAutofillObserver(authDialog);
            authDialog.show();
        }
    }

Did this work before? No 

Chrome version: 61.0.3163.100  Channel: n/a
OS Version: 10.0
Flash Version: