It is designed to be used with the native (Metacity) window decorations, instead of the custom Chrome title bar. On the Linux versions of Google Chrome and the Chromium browser, this can be enabled in the context menu of the header area (to the right of the tabs, see second screenshot).
Download this theme from here
Customized scrollbars to match the Ambiance Theme for the upcoming Ubuntu 10.04. Typically you will want to install it together with the Ambiance Theme for Chrome. However, it has no dependencies on either of these themes, so it can be used independently and should also work on Windows and MacOS.
Download Ambiance Scrollbar from here