Also moves WebContentClient and the references to the generated IPC
descriptions, since they are all components of OutOfProcessWebView.
This patch has no functional changes.
Up and down arrows now select search results. Matching index now
displays in full before filtering. Searching from the command
line focuses the query, and searches are now case insensitive.
Converts Help's layout to GML, propagates model and icon creation
errors, and switches to the MainWidget-namespace organization
pattern seen in more up-to-date apps like TextEditor to make things
easier to maintain going forward.
