This PR adds the linux and windows target platform enum values, along with automatically setting the defaultTargetPlatform to the appropriate value on those platforms.

Fixes #31366

[a11y] Make sure RenderFractionalTranslation updates its semantics after the translation field is set (#48985)

Add TargetPlatform.macOS tests to cupertino, foundation, rendering, and services libraries. (#45644)

* 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 fixes https://github.com/flutter/flutter/issues/39277

The following tests cover this change:
- packages/flutter/test/foundation/service_extensions_test.dart
- packages/flutter/test/scheduler/scheduler_test.dart

This reverts commit 6ef80b44.

This is the continuation of https://github.com/flutter/engine/pull/11041 and https://github.com/flutter/flutter/pull/38574

This is not a breaking change as we're not removing `onReportTimings` API.
We're simply removing the use of it in our framework.

* Moved the default BinaryMessenger instance to ServicesBinding

This reverts commit 821602ae.

* Added assertion in defaultBinaryMessenger. Also fixed the devicelab tests.

Filed: https://github.com/flutter/flutter/issues/38838
to track these usages.

This was introduced by: https://github.com/flutter/engine/pull/11041

This reverts commit 92ef2b9c.

This requires either runApp() or
WidgetsFlutterBinding.ensureInitialized() to have been called before
using any MethodChannels. Plugins broadly rely on MethodChannels and
right now there's no general requirements that they be constructed
within the runApp call, so the ecosystem breakages from this are broader
than originally thought. Reverting for now.

[web][upstream] Don't register exit/saveCompilationTrace for web platform since they are not available (#37812)

* Don't register N/A services exit/saveCompilationTrace for web platform

This relands https://github.com/flutter/flutter/pull/35297

The followings have been done to fix the broken tests:
  1. Add `didSendFirstFrameRasterizedEvent` extension and its tests
  2. Wait for `didSendFirstFrameRasterizedEvent` instead of
     `didSendFirstFrameEvent` during start up tests
  3. Mark missed (probably newly added) start up tests as flaky

This reverts commit 68fc7231.

This should fix https://github.com/flutter/flutter/issues/31442 and https://github.com/flutter/flutter/issues/34867

* Deprecates `BinaryMessages` in favor of a default instance of `BinaryMessenger`, called `defaultBinaryMessenger`
* Platform channels use the `defaultBinaryMessenger` for their binaryMessenger default argument.

Make FlutterError objects more structured so they can be displayed better in debugging tools such as Dart DevTools.

* Check for invalid elevation usage in the layer tree

* some space formattings

* always use blocks in if-else if a block is used

* format spaces in for and while

* allow multiline if conditions

* fix missing space

* add trailing commas on list/map/parameters

* add trailing commas on Invocation with nb of arg>1

* add commas for widget containing widgets

* add trailing commas if instantiation contains trailing comma

* revert bad change

* Add didSendFirstFrameEvent service extension.

* Switch over to the new name for compilation trace native function.

Also see: https://github.com/flutter/engine/pull/7256

* rename

* roll the engine

This reverts commit 8e2ca93f.

Fixes https://github.com/flutter/flutter/issues/23172

* Future<void> main

* Future<void>.delayed

* prefer_void_to_Null

* address review comments

Service extensions can only be activated in debug or profile mode, their code should never be included in release mode. This PR adds guards around all service extension registration calls that enable Dart's tree shaker to remove the extension's code in release mode, which reduces our binary size:

Android Snapshot (uncompressed): minus 127,384 Bytes (-124.40KB)
APK (compressed): minus 38,136 Bytes (-37.24KB)
iOS Snapshot (App.framework, uncompressed): 264,304 Bytes(-258.10KB)

For details: https://docs.google.com/document/d/13JlgvliCn5sWwT2K2SfDwD1NhEfxpJH9DCf22gZZru8/edit

**Benchmark Regressions:** This PR may cause benchmarks to regress because it may change the timing of GC. If you notice a benchmark regression **please note down the exact set of benchmarks that regressed on this PR** and then feel free to revert. I will follow-up with a PR that forces a GC before the effected benchmarks run to get a clean baseline before re-applying this PR.

* expose the debugProfileBuildsEnabled flag as a service extension

* fix tests

* review comments

* remove a new keyword

* test fixes

* review comments

Add back screenshot extension that was temporarily disabled.

Add matchesReferenceImage matcher to test that the screenshot extension
generates equivalent images to InspectorService.instance.screenshot.