This doesn't follow the spec to a tee. Our OutOfProcessWebView already
has a bitmap that can be used as the window screenshot. Therefore, we
can bypass the steps that assume we need to access the window's frame
buffer in-flight.
We also don't create an HTMLCanvasElement. We would need a Document in
the WebDriver process to do so. Instead, we can still run the encoding
steps exactly as-is using the screenshot bitmap.
WebDriver aims to implement the WebDriver specification found at
https://w3c.github.io/webdriver/webdriver-spec.html . It's an HTTP
server that can create Browser sessions and control them.
Co-authored-by: Florent Castelli <florent.castelli@gmail.com>
