Currently you lose your scroll and drawer state when coming back from the settings pane.
I think we should solve this by having the Navigator maintain a Stack and
keeping the StockHome alive underneath it. But this is good enough for a first iteration.
R=abarth@chromium.org, abarth
Review URL: https://codereview.chromium.org/1191153002.
The underlying problem is that we lacked a RenderObjectWrapper for the
RenderView, which meant we couldn't handle changing the RenderObject that was
the root of the RenderView. This CL introduces a RenderViewWrapper and uses it
in a new AppContainer widget root. This change allows us to make App a
non-magical Component that is inserted into the AppContainer in the newly
introduced runApp function.
R=ianh@google.com
Review URL: https://codereview.chromium.org/1184823006.
