This is how WebContent::ConnectionFromClient also behaves. Returning the
element as a DOM::ParentNode isn't quite strict enough for upcoming
endpoints.
Note that this does nothing to "fix" how element references are created.
We continue to return the element ID because, otherwise, all other
element WebDriver endpoints would break.
On the bright side, we avoid several IPC round trips now that we perform
the entire 'find' operation in the WebContent process; and we are able
to work directly on DOM nodes.
This moves setting the navigator.webdriver flag from after WebContent
creates the WebDriver connection, to its own IPC to be triggered from
WebDriver. This is closer to the spec, but mostly serves as an easy
test to validate the connection.
This just sets up the infrastructure for the WebContent process to house
WebDriver IPCs, and adds an IPC for WebContent to create the WebDriver
connection. The WebDriverConnection class inside WebContent ultimately
will contain most of what is currently in WebDriver::Session (so the
copyright attributions are copied here as well).
The socket created by WebDriver is currently /tmp/browser_webdriver
(formatted with some IDs). This will be moved to the /tmp/webdriver
folder, as WebDriver will create multiple sockets to communicate with
both Browser and WebContent as the IPCs are iteratively moved to
WebContent. That path is unveiled here, though it is unused as of this
commit.
