This reverts commit 12a37478.

The fuchsia code around metrics and sizing was just sending this
information through a side-channel, when the engine already had the
information available. So, delete all of it to make future CLs simpler.

Additionally, the SceneUpdateContext has many unneccesary dependencies
re: metrics and PaintTasks. Break those to make future CLs simpler.

Tested: Ran all unittests and ran workstation on Fuchsia
BUG: 53062, 53063

* Manual merge or Dart into flutter a3815b6590...24c7666def

dart-lang/sdk@24c7666def Update tests that have the current version number hardcoded
dart-lang/sdk@f88ce7aef5 Increase Dart version to 2.10

* Update language version.

* Update license.

* Hpdate language version.

* Update license.

* use Object for operator==

* apply style guide for operator==

* apply null safety syntax to mobile dart:ui

1. Simple "GPU thread" to "raster thread" replacement.

2. Regex replace "GPU([\n\r\s]+//+ thread)" with "raster$1".

3. Regex replace "// gpu$" with "// raster".

4. Simple test change.

5. Run ci/format.sh

preserve Window callback zones

* opt out dart:ui from nnbd

* Annotate tests as well

Broke a fake implementation of Accessibility features in the framework.
While this change is unlikely to break any users in the wild, this is a
breaking change by the standards set out in our documentation and
should follow the breaking change announcement process. Details can be
found at https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes.

The error in question:

    Missing concrete implementation of 'getter AccessibilityFeatures.onOffSwitchLabels' • packages/flutter_test/test/window_test.dart:252:7 • non_abstract_class_inherits_abstract_member

This reverts commit d12f2a60.

This reverts commit 8ebb3184.

This doc update solves our TODO in https://github.com/flutter/flutter/pull/43676/files#diff-6a35a9a692c9af7473ba1a0a74c979c8R223

This reverts commit 1bfb928e.

* Reland "Added new lifecycle enum (#11913)"

This reverts commit 02a47900.

Since this is currently only meant to be used by the embedding internally, the setter in Objective-C is only exposed via the FlutterDartProject private class extension. Unit tests have been added to the shell_unittests harness.

Fixes https://github.com/flutter/flutter/issues/37641

This reverts commit 147d0c38.

This reverts commit e97ed36e.

Reason for revert: Stream is considered a bad API: https://github.com/flutter/engine/pull/11041#issuecomment-526892247

Without this, developers have to override `onReportTimings` to listen for `FrameTiming`.
That can potentially break previous `onReportTimings` listeners if they forget to call
the old listener in their new callback.

This PR replaces the similar RP in the framework: https://github.com/flutter/flutter/pull/38574

Once this PR landed, we'll have to create another framework PR to use the stream to replace
`onReportTimings` usages.

Once that's done, we can then propose the breaking change of removing the deprecated
`onReportTimings`.

* Pass Android Q system gesture inset information from insets.systemGestureInsets to Window.systemGestureInsets