This reverts commit 67ffe1c2.

This PR adds the full framework stack (layer->render object->widget, and
service) for embedding iOS views with minimal functionality.

I allowed myself to throw the entire framework stack in one PR since we're mostly
mirroring the structure we already established for embedded Android views, so this PR
is a little bigger than usual. I'm happy to break it down to the
different pieces of the stack if reviewers prefer.

Specifically this PR adds:
* A UiKitView widget for embedding a UIView in the widget tree.
* A RenderUiKitView which is the render object for showing a
  UIView.
* A PlatformViewLayer which denotes the position of a UIView in the
  layer tree.
* The iOS platform_views system channel client code in services/platform_views.dart
* Splits the fake platform views controller to an Android and iOS
  controllers.

TBD in following PRs:
* Plumb the layout direction all the way to the platform view (currently
  there is still no engine support for it).
* Integrate with gesture arenas (engine support is still missing as
  well).

* [Material] Add dialog theme.

* Address Hans' first round comments.

* Address Hans' Second round comments.

* Fix theme tests

* Address Will's comments, add golden test

* Update goldens

* Custom Border radius 16.0

* Address Hans' Comments

* Second round comments

* fix imports

* Create TabBarTheme of(...) constructor

* First round comments

* fix imports

This adds flutter create --sample which allows users to execute a command which will create a working sample app from samples embedded in the API docs.

The command looks something like this:

flutter create --sample=chip.DeletableChipAttributes.onDeleted mysample

Stop wrapping adb, gradle and ios logger output, and update terminal wrapping column dynamically. (#23592)

Subcommand output (gradle, adb, etc) is no longer wrapped, and wrapping notices when the terminal column width changes dynamically now.

Fixes #23267.
Fixes #23266.

* Adds sample code to TextFormField

* update the docs for the module template

* update text

* added textDirection to TextField

* Revert "Update templates (#23698)"

This reverts commit 5b0de6d6.

* Revert "Verify that date/number translations exist for all supported languages (#23692)"

This reverts commit 3449edf2.

* Revert "Reland Xcode backend refactor (#23574)"

This reverts commit 7270f284.

Removes some `new`s and other minor cleanup.

* Use Xcode build configurations to drive Flutter build mode

* Proper check wrt local_engine, print error if profile mode misisng

* Remove unused code, update tests, fix template problem, update warning

* fix up warning

* add explanatory dev comment

* fix whitespace

* missing words, change lambda arrow to function body

* error indentation

* Test early exits for xcode_backend.sh

* only on macOS, use right test

* Update error messages

* case insensitive compare for build config

* Update gallery podfile

* update projects to add profile configuration

* make compatible with flavors

* add missing plist files

* Update template comments

Make template comments consistent with recent tools changes

* Update packages/flutter_tools/templates/app/lib/main.dart.tmpl
Co-Authored-By: mit-mit <mit-mit@users.noreply.github.com>

* Fix merge conflict

https://github.com/flutter/engine/compare/7be0217d6796...3a6775730028

git log 7be0217d6796..3a6775730028 --no-merges --oneline
3a6775730 Roll src/third_party/skia 14768f64fba3..dde307f14273 (3 commits) (flutter/engine#6697)
ab92772e8 Roll src/third_party/skia ca44d5d85895..14768f64fba3 (1 commits) (flutter/engine#6695)
d7e2be279 Roll src/third_party/skia d48b7a881b24..ca44d5d85895 (3 commits) (flutter/engine#6694)


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162b2e98c036a8f8c355fd475dbe0db4f4bc886c..7be0217d6796954694753647b7a757b8e3907f64
7be0217d6 Roll back _countryCode assert - breaking change (#6693)
91a019cfd Fix popSystemNavigator (#6691)
2b2fbf0f6 Add Locale.fromSubtags and support for scriptCode. (#6518)
58c8e30e5 Roll src/third_party/skia ab18c8e6cc20..d48b7a881b24 (5 commits) (#6690)
3b17cfb68 Flutter tester default locales (#6689)
96bbd2b36 Roll buildroot to 11a934e99eaa4aa8e278cd2772aff4f51f1f3c41 (#6687)
0e9defbd6 Roll src/third_party/skia 68825776f4b4..ab18c8e6cc20 (11 commits) (#6688)
cc686d7ae Don't populate the external view embedder in PaintContext. (#6686)
ab782faa7 Roll src/third_party/skia 1de48d8040aa..68825776f4b4 (1 commits) (#6685)
c4aa8d343 Roll src/third_party/skia 797197a772b8..1de48d8040aa (2 commits) (#6684)
7352251eb Roll src/third_party/skia 79c96811863f..797197a772b8 (1 commits) (#6683)
3dac47e4d Roll src/third_party/skia 38e4fd0c5654..79c96811863f (1 commits) (#6682)
2f06a53a8 Roll src/third_party/skia b53f1f46982d..38e4fd0c5654 (1 commits) (#6681)
a1d7cad70 Fix inconsistent include syntax (#6680)
236661cd8 Roll src/third_party/skia 3b79aa3a5ad0..b53f1f46982d (13 commits) (#6679)
c4f50611d Roll buildroot to pick up Mac toolchain updates. (#6678)
ba8f6aa71 Handle Windows headers defining ERROR to 0 in log levels. (#6677)
505d2a923 Roll buildroot to pick up updates to custom toolchains. (#6674)
6c2a0b3a6 Undefine ERROR in platform_view_layer.cc (#6675)
55e12993a Update FlutterPlugin.h docs, suppress warning for older API (#6672)
f7970048d Attach and position embedded UIVIews (#6614)
df85722fa Plumb the iOS PlatformViewsController into flow. (#6603)
2bfb893cf iOS Embedding Refactor (#6447)

Luckily this class didn't actually need to extend its superclass, it
only implements the interface. So we can change `extends` to
`implements` and that's close enough, while allowing the class to be
mixed in again.

* Avoid abbreviations

* Sample code for AppBar.leading

* Add a test for OverflowBox/FractionallySizedBox

* Minor wording improvements in the text.

The words "note that" here don't really contribute to the flow.

* Revert "Revert "Run reload asynchronously so that multiple devices can reload in parallel. (#22693)" (#23598)"

This reverts commit 0b68068d.

* Fix refreshViews so it sends app-wide(rather than per-isolate) service request.

Sending per-isolate request caused dead-lock in the engine in case of more-than-one ui isolate.

* Added '--check-for-remote-artifacts' option for Flutter Doctor.

This option takes a Flutter engine revision and issues HEAD requests to
determine whether or not artifacts for the provided engine revision are
available from cloud storage. This functionality is needed for the Dart
SDK autoroller to avoid creating a PR to roll the engine into the
framework while artifacts haven't finished building, which would cause
Cirrus tests to fail.

Previously there was no way to add this flag when searching for
Isolates.

One of the devicelab tests is broken after this commit - rolling to last known good commit while I investigate.

/cc @bkonyi

https://github.com/flutter/engine/compare/2f06a53a8d19...7352251ebec6

git log 2f06a53a8d19..7352251ebec6 --no-merges --oneline
7352251eb Roll src/third_party/skia 79c96811863f..797197a772b8 (1 commits) (flutter/engine#6683)
3dac47e4d Roll src/third_party/skia 38e4fd0c5654..79c96811863f (1 commits) (flutter/engine#6682)


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https://github.com/flutter/engine/compare/a1d7cad70c81...2f06a53a8d19

git log a1d7cad70c81..2f06a53a8d19 --no-merges --oneline
2f06a53a8 Roll src/third_party/skia b53f1f46982d..38e4fd0c5654 (1 commits) (flutter/engine#6681)


The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

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If the roll is causing failures, please contact the current sheriff, who should
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https://github.com/flutter/engine/compare/162b2e98c036...a1d7cad70c81

git log 162b2e98c036..a1d7cad70c81 --no-merges --oneline
a1d7cad70 Fix inconsistent include syntax (flutter/engine#6680)
236661cd8 Roll src/third_party/skia 3b79aa3a5ad0..b53f1f46982d (13 commits) (flutter/engine#6679)
c4f50611d Roll buildroot to pick up Mac toolchain updates. (flutter/engine#6678)
ba8f6aa71 Handle Windows headers defining ERROR to 0 in log levels. (flutter/engine#6677)
505d2a923 Roll buildroot to pick up updates to custom toolchains. (flutter/engine#6674)
6c2a0b3a6 Undefine ERROR in platform_view_layer.cc (flutter/engine#6675)
55e12993a Update FlutterPlugin.h docs, suppress warning for older API (flutter/engine#6672)
f7970048d Attach and position embedded UIVIews (flutter/engine#6614)
df85722fa Plumb the iOS PlatformViewsController into flow. (flutter/engine#6603)
2bfb893cf iOS Embedding Refactor (flutter/engine#6447)


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* Revert "[H] Created a variant of InheritedWidget specifically for Listenables (#23393)"

This reverts commit 93132859.

* Revert "Fix a race condition in vmservice_test.dart (#23529)"

This reverts commit 5e7b0a36.

* Created a variant of InheritedWidget specifically for Listenables

* Add more documentation per review comments

Fixes https://github.com/flutter/flutter/issues/19273

This reverts commit 0f34f526.

Reverts flutter/flutter#23612 as it broke the following two bots:
1. platform_view__start_up
2. platform_interaction_test_ios

Merge on red to fix the rope.

https://github.com/flutter/engine/compare/162b2e98c036...6c2a0b3a6d93

git log 162b2e98c036..6c2a0b3a6d93 --no-merges --oneline
6c2a0b3a6 Undefine ERROR in platform_view_layer.cc (flutter/engine#6675)
55e12993a Update FlutterPlugin.h docs, suppress warning for older API (flutter/engine#6672)
f7970048d Attach and position embedded UIVIews (flutter/engine#6614)
df85722fa Plumb the iOS PlatformViewsController into flow. (flutter/engine#6603)
2bfb893cf iOS Embedding Refactor (flutter/engine#6447)


The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

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