UserAgent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36

Steps to reproduce the problem:
1. Connect Android device to Linux PC by USB.
2. Load Chrome (or Chrome Beta or Chrome Unstable) on Linux.
3. Go to chrome://inspect/#devices.
4. Click the "inspect" link to inspect an open page on the Android device.

What is the expected behavior?
I used to be able to inspect Chrome on Android using Chrome on Linux. If I use Chrome on Windows, then it works.

What went wrong?
When clicking the "inspect" link, a new window opens with "chrome-devtools://devtools/remote/serve_rev/..." in the title bar, but the window is otherwise blank.

If I use DevTools to inspect that blank window, it shows the following in the console:

Uncaught TypeError: Cannot read property 'addExtensions' of undefined

The source link points to this code from devtools.js:

    addExtensions: function(extensions)
    {
        // Support for legacy front-ends (<M41).
        if (window["WebInspector"].addExtensions)
            window["WebInspector"].addExtensions(extensions);
        else
            this._dispatchOnInspectorFrontendAPI("addExtensions", [extensions]);
    }

Should that if statement be the following instead?

        if (window["WebInspector"] && window["WebInspector"].addExtensions)

Did this work before? Yes It worked a few weeks ago, but I don't have version details.

Chrome version: 51.0.2704.63  Channel: beta
OS Version: 
Flash Version: