Almost. There is no confusion, rest assured. They are both proprietary, but one of them likes to act as if it was open source (see also: Android), and clearly it hides well.
Android as far as I know uses a source-drop model. For both WebKit and Chromium, all code reviews are as far as I know done publicly.
AOSP is open source, but Android itself is far from it - just ask Huawei. More and more code is in proprietary bits of Google code. And Chromium is not Chrome, most people use Chrome builds which are proprietary.