* Relicense Shrine demo to match rest of repository

The Shrine demo was Apache-licensed. The code was mostly
Google-written, with contributions from:

 - Michelle Dudley (@michdud)

 - Abhijeeth Padarthi <rkinabhi@gmail.com> (@rkinabhi)

 - @a14n

I contacted all three, and they confirmed their approval for this
change, as described below.

Abhijeeth Padarthi said by e-mail on Thu, Nov 21, 2019 at 5:48 PM:

> hi Ian,
>
> sure :)
>
> let me know if I need to do anything on my end..

Michelle Dudley wrote by e-mail on Sun, Nov 24, 2019 at 2:07 PM:

> Hi Ian,
>
> That would be ok with me.
>
> Thanks,
>
> Michelle

@a14n said on Discord's Flutter server in the #hackers channel at 10:44PM on Thursday, November 21, 2019:

> @Hixie no problem I agree with this relicensing

* Remove shrine loophole from license checker.

* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

This PR adds TargetPlatform.macOS to the TargetPlatform enum. This allows us to begin implementation of some adaptive UI based on which target platform is desired.

I haven't updated the tests here, that will come in a follow-up PR.

* make BuildContext.{ancestorStateOfType,ancestorRenderObjectOfType,rootAncestorStateOfType} generic

* make BuildContext.inheritFromWidgetOfExactType generic

* make BuildContext.ancestorInheritedElementForWidgetOfExactType generic

* make BuildContext.ancestorWidgetOfExactType generic

* fix snippet

* bump scoped_model on temp version

* update names

* Revert "bump scoped_model on temp version"

This reverts commit d1fcbba028cdb07f44738d1652391692d1ea5ec0.

* address review comments

* fix ci

* address review comments

* repeat the deprecation notice

* fix uppercase

* use of recommanded deprecation syntax

* address review comment

Reverting since https://github.com/flutter/flutter/commit/2c7af1e24e45a79f4eb73d67d98fcecea8bf6146
reverted the original commit that required this in the first place.

This reverts commit 68d1fe58.

Typo in a title in a gallery demo

This reverts commit 399aebc4.

It contained Apache 2.0 licensed files, which aren't allowed in flutter/flutter

This reverts commit 421bf647.

Was causing severe breakages in Google.

Update the Slider and RangeSlider to the latest Material spec. This introduces an updated track, updated thumbs, updated tick marks, and a new value indicator shape. The old paddle value indicator shape is also updated so that text scaling works consistently.

This will catch issues like
https://github.com/flutter/flutter/issues/44252, and this test is
inspired by the `list_demo` sample app in
https://github.com/flutter/flutter/issues/43083#issue-509586473

This is tested locally on a Moto G4 before and after the fix
https://github.com/flutter/engine/pull/13710

The `average_frame_rasterizer_time_millis` of this test drops from
~5.4ms to ~4.9ms after that fix.

Add Material Study app Rally as an example app

While building the iOS platform views support we only enabled it when the app developer explicitly specified it with a flag, the main reasons were using an untested thread configuration, and taking a performance hit (even when no platform view is used due to disabled raster cache).

Now that we are using the same dynamic thread configuration whether platform views is used or not, and that raster cache works with platform views in the tree as well, we are almost ready to enabled the platform views support by default.

As a first step, I'm enabling it for the Flutter Gallery app on which we run benchmarks. After monitoring the benchmarks and making sure the gallery takes no hit we should be more confident to enabled platform views by default.

This change is expected to have no performance effect on the Gallery app at all.

Updated flutter/examples to further conform to new embedding: removed references to FlutterApplication, deleted all MainActivity's that were not necessary, removed all direct invocations of GeneratedPluginRegistrant. (#22529) (#44782)

See https://github.com/flutter/flutter/issues/9257#issuecomment-550503833

This reverts commit a214b462.

* Add Material Study app Rally to examples

This reverts commit 99cd4403.

This reverts commit 46edc802.

* Fix device lab tests

* Migrate examples to the Android embedding v2 (#43221)

This reverts commit b49ffa81.

This adds a canRequestFocus and skipTraversal argument to FocusScope and FocusScopeNode, so that a scope can prevent being traversed.

This allows a fix for a problem in the gallery where the focus while traversing the list of items would sometimes appear to disappear, since it would be focusing things that were in the backdrop that were part of the tree, but were not visible.

Related Issues
Fixes #42955