A new WM bootstrap flow

As discussed, a new WM bootstrap flow.

First off, create a new window manager app (wm_flow_wm) which uses the core_window_manager_lib static lib to implement a basic WM.

Second, create a new demo launcher (wm_flow_init) that starts the view manager, embeds wm_flow_wm, and starts an additional app (wm_flow_app).

Thirdly, creates an additional app (wm_flow_app) that also connects to the view manager init service and asks it to embed it somewhere, thus giving it a connection to the view manager (and a top-level window).

I had to change ViewManagerInitService to have some shared state so that it was possible to connect to it > 1 time.

R=sky@chromium.org
BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=285345

[sky, 2014-07-24 16:43:28]

LGTM

https://codereview.chromium.org/400113005/diff/160001/mojo/examples/wm_flow/a...
File mojo/examples/wm_flow/app/app.cc (right):

https://codereview.chromium.org/400113005/diff/160001/mojo/examples/wm_flow/a...
mojo/examples/wm_flow/app/app.cc:23: class WMFlowApp : public
mojo::ApplicationDelegate,
Please add descriptions to your classes. It helps when random people come and
look at things and wonder what's what. Additionally it might help to document
how all these fit together in a document (basically what you have in the
description of this patch).

https://codereview.chromium.org/400113005/diff/160001/mojo/mojo.gyp
File mojo/mojo.gyp (right):

https://codereview.chromium.org/400113005/diff/160001/mojo/mojo.gyp#newcode121
mojo/mojo.gyp:121: 'mojo_wm_flow_init',
nit: sort.

https://codereview.chromium.org/400113005/diff/160001/mojo/services/view_mana...
File mojo/services/view_manager/view_manager_init_service_context.cc (right):

https://codereview.chromium.org/400113005/diff/160001/mojo/services/view_mana...
mojo/services/view_manager/view_manager_init_service_context.cc:54:
(*it)->OnRootViewManagerWindowTreeHostCreated();
The ordering here feels very fragile. In so far as it seems easy to accidentally
give the wrong connection all priviledges. Maybe we should tag the first
connection specially so that when we EmbedRoot we can verify we really want to
give it all permissions.

https://codereview.chromium.org/400113005/diff/160001/mojo/services/view_mana...
File mojo/services/view_manager/view_manager_service_impl.h (right):

https://codereview.chromium.org/400113005/diff/160001/mojo/services/view_mana...
mojo/services/view_manager/view_manager_service_impl.h:17: #include
"mojo/services/view_manager/node.h"
It doesn't seem like this should be necessary.

[Ben Goodger (Google), 2014-07-24 19:04:56]

Committed patchset #11 manually as r285345 (presubmit successful).