Move wm_flow off of views and onto Sky

Move wm_flow off of views and onto Sky

This is a proof of concept for replacing ui/views
code with Sky instead. erg says this will allow him
to delete 10s of thousands of LOC from mojo.

Mojo does not yet expose the current binary's URL:
https://docs.google.com/a/chromium.org/document/d/1AQ2y6ekzvbdaMF5WrUQmneyXJnke-MnYYL4Gz1AKDos
So I've worked around that by passing the url
of the binary via the helper script.

I discovered several bugs in the wm_flow code
including that it doesn't handle view resizes
(during embiggen).  Related, I discovered that
every time a new window is made it drops the
connections to the embedded.cc app from the
previous window, since the ViewManagerDelegate
is incorrectly implemented as part of the
ApplicationDelegate on both app.cc and embedded.cc.
We'd need to split out a separate per-view object
in both of those apps to handle the
ViewManagerDelegate calls.

There are some changes to logging during loading
as well as the CopyToFile helper to have better
error reporting.  I hit several issues early on trying
to get mojo to load the http: urls correctly, including
eventually running out of disk space on my /tmp
and mojo then silently failing to launch the app
(due to mojo never clearing its caches crbug.com/446302).

I had to re-write the mojo_demo.sh script in python
as well as split the sky_server handling code out of
skydb into a separate python module in order to cleanly
launch sky_server.  We could use a separate server
if we wanted to but the primary benefit of sky_server
is that it sets up the proper url->disk mappings into
the generated file directories, etc.

BUG=443439
R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/72d6a21732cdc95202ef9a333d9f063bf93cc534

[eseidel1, 2014-12-19 02:29:40]

eseidel@google.com changed reviewers:
+ eseidel@google.com

[eseidel1, 2014-12-19 02:29:40]

I'll solve the resources problem tomorrow by just making wm_flow url-hosted and
have mojo_demo.sh launch sky_server.

The connection-specific-services should also be just a few lines of code in
internals.cc

[eseidel, 2014-12-19 21:39:46]

Much closer to working.  Still several problems:

1.  Only the first window seems to load.
2.  Only one pair of the embedded apps seems to load.
3.  Any click seems to trigger embiggen.
4.  Background color of the window is not drawing blue?
5.  The embedded app is not drawing.
6.  Need some solution for the various hard-coded urls.

[eseidel, 2014-12-20 00:39:46]

So my issue blocking me right now is that when sky is put in a mojo view at
offset x, x, something ends up clipping sky at 2x, 2x.  The translate is applied
twice.  Not sure what.  Will find out in the new year!

[jamesr, 2014-12-30 01:21:32]

jamesr@chromium.org changed reviewers:
+ jamesr@chromium.org

[jamesr, 2014-12-30 01:21:33]

There's a general issue right now with transforms being applied multiple times. 
This code has changed in surface_aggregator recently so I'm not sure if we're
passing bad transforms in or of it's merging them incorrectly.  Will
investigate.

I don't think this issue is specific to sky since the (non-sky) wm_flow and
other demos show the same issue.

[eseidel, 2015-01-05 22:08:09]

James fixed the translation error in:
https://codereview.chromium.org/822903003/

The next biggest problem is that app.cc (and thus embedded.cc) only appears to
load once.  Also neither are drawing (although I'm able to click on their
invisible selves and launch new windows).

[eseidel, 2015-01-05 22:14:17]

If I remove the code which embeds sky in the view then the subviews draw
correctly.  Presumably sky doesn't know how to correctly composite random mojo
subviews.

[eseidel, 2015-01-06 00:11:49]

Nearly ready for review.  I should probably land this in pieces.

[eseidel, 2015-01-06 20:55:12]

I think we can start the reviewing process.  I still need a solution for mapping
both /examples as well as /gen/examples into the url space.

[jamesr, 2015-01-06 20:56:34]

jamesr@chromium.org changed reviewers:
+ sky@chromium.org
- eseidel@google.com

[jamesr, 2015-01-06 20:56:34]

I think Scott might be a better reviewer (if he's able) - I really don't know
much about the window manager / view manager interactions.

[abarth-chromium, 2015-01-06 21:20:42]

abarth@chromium.org changed reviewers:
+ abarth@chromium.org

[abarth-chromium, 2015-01-06 21:20:43]

lgtm

https://codereview.chromium.org/817573003/diff/180001/examples/wm_flow/wm/win...
File examples/wm_flow/wm/window_frame.sky (right):

https://codereview.chromium.org/817573003/diff/180001/examples/wm_flow/wm/win...
examples/wm_flow/wm/window_frame.sky:69: return shell.wrapHandle(handle,
service, client);
This should be in Sky

https://codereview.chromium.org/817573003/diff/180001/mojo/tools/mojo_demo.py
File mojo/tools/mojo_demo.py (right):

https://codereview.chromium.org/817573003/diff/180001/mojo/tools/mojo_demo.py...
mojo/tools/mojo_demo.py:33: print mojo_shell, args.build_dir
print!

[eseidel, 2015-01-06 21:21:40]

eseidel@chromium.org changed reviewers:
+ erg@chromium.org
- jamesr@chromium.org, sky@chromium.org

[sky, 2015-01-06 21:26:55]

sky@chromium.org changed reviewers:
+ sky@chromium.org

[sky, 2015-01-06 21:26:56]

https://codereview.chromium.org/817573003/diff/180001/examples/wm_flow/app/ap...
File examples/wm_flow/app/app.cc (left):

https://codereview.chromium.org/817573003/diff/180001/examples/wm_flow/app/ap...
examples/wm_flow/app/app.cc:139: void OpenNewWindow() {
view_manager_context_->Embed("mojo:wm_flow_app"); }
Why do you need to change this and 108?

https://codereview.chromium.org/817573003/diff/180001/mojo/tools/mojo_demo.py
File mojo/tools/mojo_demo.py (right):

https://codereview.chromium.org/817573003/diff/180001/mojo/tools/mojo_demo.py...
mojo/tools/mojo_demo.py:45: cmd.append('--v=1')
Seems like the --v=1 should be a separate switch, or always added (meaning for
--browser too).

[eseidel, 2015-01-06 21:48:18]

https://codereview.chromium.org/817573003/diff/180001/examples/wm_flow/app/ap...
File examples/wm_flow/app/app.cc (left):

https://codereview.chromium.org/817573003/diff/180001/examples/wm_flow/app/ap...
examples/wm_flow/app/app.cc:139: void OpenNewWindow() {
view_manager_context_->Embed("mojo:wm_flow_app"); }
On 2015/01/06 21:26:55, sky wrote:
> Why do you need to change this and 108?

Sky has multi-file dependencies.  When you load "window_frame.sky" (which was
written for this change) it depends on /sky/framework/sky-element.sky for
example, which means that either I need to change those dependency paths to be
file-paths, or I need to run an http server to serve them.  If I'm running an
http server to serve them, then I might as well serve the mojo apps off of http
as well.  If I only change some of the references to wm_flow_app to http urls
then it will end up loaded twice (once as mojo:wm_flow_app and a second time as
the http url.  I guess I could use the url-mapping functionality of mojo_shell
to map them all to mojo:urls, but it seemed easier to just use http everywhere
since that's more like what our eventual deployment environment will be.

[eseidel, 2015-01-06 22:40:46]

Committed patchset #11 (id:200001) manually as
72d6a21732cdc95202ef9a333d9f063bf93cc534 (presubmit successful).

[eseidel, 2015-01-06 22:47:40]

Spoke with sky and beng in person.  Hopefully we'll make this path smooth. 
Loading from http urls seems inevitable given our current plans of being
ephemeral.