* Add a tool for running Android SDK lint on Android embedding

Adds support for system text scale factor, including hooks for Android system settings changes.  iOS hooks will be added in another PR.

* Namespaces have been updated to reflect the move from //flutter/sky/shell to //flutter/shell.
* shell/BUILD.gn file has been split into smaller GN files for each subcomponent of the shell (common, GPU, diagnostic, testing).
* GN dependencies have been rewritten to stop exposing common shell dependencies as public. Duplicates have also been removed.
* GPU subcomponent has been updated make it more suitable for Vulkan integration.
* The GLFW backend has been resurrected.

Now that we understand window insets, we don't need to hard-code the size of
the status bar. Also, convert the viewport metrics to be consistently in
physical pixels.

This patch prepares us to add support for Mozart.

This patch makes it easier to work with SkyShell on non-rooted devices.

Very simple so far. This schedules an alarm to fire once a day, kicking
off a service that downloads a new app.skyx from a hardcoded URL. The
new skyx replaces the current one.

This CL introduces a SkyShell.apk that is separate from the SkyDemo.apk that we
upload to the store to show our demos.  The SkyShell.apk is just an empty shell
that can run Sky applications on Android.

Also fixed roll_versions to no longer roll mojo paths
since those are not part of the sky_engine repository.

R=abarth@google.com

Using this theme appears to remove the white flash during startup.

R=eseidel@chromium.org, jackson@google.com

Review URL: https://codereview.chromium.org/1240433004 .

TBR=johhmccutchan@google.com

Review URL: https://codereview.chromium.org/1231413004 .

BUG=

Review URL: https://codereview.chromium.org/1231803003 .

BUG=
R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1231653002 .

TBR=abarth@google.com

Review URL: https://codereview.chromium.org/1222193008 .

TBR=abarth@google.com

Review URL: https://codereview.chromium.org/1216053015 .

R=eseidel@chromium.org, eseidel@google.com

Review URL: https://codereview.chromium.org/1214633008 .

Offline support isn't complete, but after this CL, SkyDemo.apk is able to start
and show some UI offline.

R=eseidel@chromium.org, eseidel@google.com

Review URL: https://codereview.chromium.org/1225883002.

This CL switches SkyDemo over to using explicit intents for deciding which Sky
apps to run. This change lets us get rid of the hacky "sky" URI scheme.
Instead, we use normal URLs but we require the sender of the intent to be
explicit in directing the VIEW intent to us.

TBR=eseidel@google.com

Review URL: https://codereview.chromium.org/1221123003.

TBR=abarth@chromium.org

Review URL: https://codereview.chromium.org/1219683005.

Publishing sky to fix sky_tool.

https://github.com/domokit/mojo/issues/262

TBR=johnmaccutchan@google.com

Review URL: https://codereview.chromium.org/1205653002.

TBR=abarth@chromium.org

Review URL: https://codereview.chromium.org/1197113003.

We can use these intents to move the demo launcher to the new world.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1187583002.

This is feature creep.  But it was simple and fun. :p

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1175393002.

This isn't perfect, since it makes non-minimal modifications
to the yaml and xml files.  In the yaml case it sorts the keys
and in the xml case it doesn't do the fancy attribute wrapping,
but this seems good enough to use.

R=abarth@chromium.org, johnmccutchen@google.com

Review URL: https://codereview.chromium.org/1179633003.

I'm starting to spec out a script to make these updates for me
but for now I'm still doing these by hand.

TBR=johnmccutchen@google.com

Review URL: https://codereview.chromium.org/1170863007.

Also teach both skydb and shelldb to ignore version downgrades
I did not change sky_tool since maybe the warning makes sense
there?

R=abarth@chromium.org, chinmaygarde@google.com

Review URL: https://codereview.chromium.org/1138343002

Sending out a new version to fix the hittesting bug.

TBR=abarth@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1025653005

This version updates the url it loads from /home to /sky_home
and also adds a bit of logging on 404s.

TBR=abarth@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1015243002

R=abarth@chromium.org, eseidel@chromium.org

Review URL: https://codereview.chromium.org/1018033002

TBR=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1010213004

This doesn't actually wire the icon into the apk building.
I will do that in a separate step from my linux machine.
It will require a couple lines edit in BUILD.gn

R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/d782adeb185a93c3b11168d358342b243bf87f3e

Review URL: https://codereview.chromium.org/1013323002

We now register the sensor service from SkyDemo, which shows that embedders of
SkyShell can register their own Java services.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/969753003

This CL adds a sensor_service to sky/services and wires it into SkyShell
The plan is to eventually use this data to implement shake-to-refresh.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/962043002

This CL renames SkyShell.apk to SkyDemo.apk and adds a Stocks.apk which
defaults to the stocks demo app. Sky Shell is now a library that can be
packaged by different APKs.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/965493002