## Description

Continuing the work from @jamilsaadeh97 to replace verbose null checks
with modern
[null_aware_elements](https://dart.dev/tools/linter-rules/use_null_aware_elements)
syntax.

This PR cleans up the remaining files not covered in the previous parts,
making the code more concise.

## Related PRs

- #172198
- #172306
- #172307
- #172322

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

Roll Flutter from c3279ca to 871849e (56 revisions)

flutter/flutter@c3279ca...871849e

2025-08-01 engine-flutter-autoroll@skia.org Roll Dart SDK from 6832e04cf2f9 to 6e1bb159c860 (8 revisions) (flutter/flutter#173119)
2025-08-01 derekx@google.com Add `--profile-startup` flag to `flutter run` (flutter/flutter#172990)
2025-08-01 32538273+ValentinVignal@users.noreply.github.com Add `side` to `RadioThemeData` (flutter/flutter#171945)
2025-08-01 katelovett@google.com Update GCA instructions (flutter/flutter#173001)
2025-08-01 jssaadeh@outlook.com [engine] Null aware elements clean-ups (flutter/flutter#173075)
2025-08-01 engine-flutter-autoroll@skia.org Roll Packages from db6988d to f0645d8 (3 revisions) (flutter/flutter#173111)
2025-08-01 98614782+auto-submit[bot]@users.noreply.github.com Reverts "Reland licenses cpp switch 3 (#173063)" (flutter/flutter#173113)
2025-08-01 magder@google.com Update embedder API CODEOWNERS (flutter/flutter#173081)
2025-08-01 magder@google.com Move android_obfuscate_test from devicelab into tools integration.shard (flutter/flutter#169798)
2025-08-01 jhy03261997@gmail.com [A11y] RangeSlider should have 2 focus node (flutter/flutter#172729)
2025-07-31 chinmaygarde@google.com Upload the linux arm64 embedder to cloud buckets. (flutter/flutter#173068)
2025-07-31 30870216+gaaclarke@users.noreply.github.com Reland licenses cpp switch 3 (flutter/flutter#173063)
2025-07-31 bkonyi@google.com [ Tool ] Mark IOOverrides subclasses as `final` (flutter/flutter#173078)
2025-07-31 chenmingding.cmd@alibaba-inc.com [macOS] Remove duplicate object initialization (flutter/flutter#171767)
2025-07-31 magder@google.com Redistribute Android test owners (flutter/flutter#172886)
2025-07-31 magder@google.com Avoid negatives in the styleguide.md (flutter/flutter#172917)
2025-07-31 engine-flutter-autoroll@skia.org Roll Skia from 42e3bed42110 to 49e39cd3cf18 (7 revisions) (flutter/flutter#173069)
2025-07-31 ybz975218925@gmail.com Fix the issue where calling showOnScreen on a sliver after a pinned child in SliverMainAxisGroup does not reveal it. (flutter/flutter#171339)
2025-07-31 31685655+SalehTZ@users.noreply.github.com Improve assertion message in `EdgeInsetsDirectional.resolve` (flutter/flutter#172099)
2025-07-31 30870216+gaaclarke@users.noreply.github.com licenses_cpp: Switched to lexically_relative for 2x speed boost. (flutter/flutter#173048)
2025-07-31 a-siva@users.noreply.github.com Add dartvm to the dart_sdk_entitlement_config list. (flutter/flutter#173044)
2025-07-31 mdebbar@google.com [web] ClickDebouncer workaround for iOS Safari click behavior (flutter/flutter#172995)
2025-07-31 98614782+auto-submit[bot]@users.noreply.github.com Reverts "Reland licenses cpp switch 2 (#172996)" (flutter/flutter#173059)
2025-07-31 mdebbar@google.com [web] Text editing test accepts both behaviors in Firefox (flutter/flutter#172767)
2025-07-31 30870216+gaaclarke@users.noreply.github.com Reland licenses cpp switch 2 (flutter/flutter#172996)
2025-07-31 engine-flutter-autoroll@skia.org Roll Packages from d914120 to db6988d (2 revisions) (flutter/flutter#173039)
2025-07-31 737941+loic-sharma@users.noreply.github.com Add a SliverList code sample (flutter/flutter#172986)
2025-07-31 1083941774@qq.com fix: adjust scrollable size assertion with tolerance (flutter/flutter#171426)
2025-07-31 30870216+gaaclarke@users.noreply.github.com impeller: Shrink `Command` 40 bytes (flutter/flutter#173004)
2025-07-31 mdebbar@google.com [web] Remove outdated comment about HTML renderer (flutter/flutter#172877)
2025-07-31 engine-flutter-autoroll@skia.org Roll Skia from ff4da49305c5 to 42e3bed42110 (1 revision) (flutter/flutter#173038)
2025-07-31 engine-flutter-autoroll@skia.org Roll Skia from 7d468a4868cb to ff4da49305c5 (3 revisions) (flutter/flutter#173028)
2025-07-31 engine-flutter-autoroll@skia.org Roll Skia from 951277895c86 to 7d468a4868cb (1 revision) (flutter/flutter#173027)
2025-07-31 a-siva@users.noreply.github.com Manual roll of Dart from 14ea8d342149 to 6832e04cf2f9 (flutter/flutter#173015)
2025-07-31 engine-flutter-autoroll@skia.org Roll Skia from 8bdf4cdcf4ed to 951277895c86 (2 revisions) (flutter/flutter#173022)
2025-07-31 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from bQVQlLssTxxLjoDU0... to xo_bqOoFuBKFmgKxn... (flutter/flutter#173021)
2025-07-31 31685655+SalehTZ@users.noreply.github.com feat: Add `cursorHeight` to `DropdownMenu` (flutter/flutter#172615)
2025-07-31 engine-flutter-autoroll@skia.org Roll Skia from a3347cee2d73 to 8bdf4cdcf4ed (3 revisions) (flutter/flutter#173013)
2025-07-31 bkonyi@google.com [ Widget Preview ] Add `--web-server` support (flutter/flutter#172978)
2025-07-30 jmccandless@google.com Bump customer tests for zulip fix 2 (flutter/flutter#173003)
2025-07-30 jssaadeh@outlook.com Migrate to null aware elements - Part 4 (flutter/flutter#172322)
2025-07-30 fluttergithubbot@gmail.com Marks Linux linux_feature_flags_test to be unflaky (flutter/flutter#172629)
2025-07-30 bkonyi@google.com [ Widget Previews ] Add support for `MultiPreview`s (flutter/flutter#172852)
2025-07-30 30870216+gaaclarke@users.noreply.github.com Made licenses_cpp simpatico with google licenses (flutter/flutter#172991)
2025-07-30 engine-flutter-autoroll@skia.org Roll Skia from d579722d65c6 to a3347cee2d73 (6 revisions) (flutter/flutter#172989)
2025-07-30 ricardodalarme@outlook.com Migrate to null aware elements - Part 5 (flutter/flutter#172418)
...

## Description

Continuing the work from @jamilsaadeh97 to replace verbose null checks
with modern
[null_aware_elements](https://dart.dev/tools/linter-rules/use_null_aware_elements)
syntax.

This PR cleans up the remaining files not covered in the previous parts,
making the code more concise.

## Related PRs

- flutter#172198
- flutter#172306
- flutter#172307
- flutter#172322

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

<!--
Thanks for filing a pull request!
Reviewers are typically assigned within a week of filing a request.
To learn more about code review, see our documentation on Tree Hygiene:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
-->

Replace null checks with null aware elements - part 4

Part of flutter#172188

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Description

Continuing the work from @jamilsaadeh97 to replace verbose null checks
with modern
[null_aware_elements](https://dart.dev/tools/linter-rules/use_null_aware_elements)
syntax.

This PR cleans up the remaining files not covered in the previous parts,
making the code more concise.

## Related PRs

- flutter#172198
- flutter#172306
- flutter#172307
- flutter#172322

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

<!--
Thanks for filing a pull request!
Reviewers are typically assigned within a week of filing a request.
To learn more about code review, see our documentation on Tree Hygiene:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
-->

Replace null checks with null aware elements - part 4

Part of flutter#172188

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Description

Continuing the work from @jamilsaadeh97 to replace verbose null checks
with modern
[null_aware_elements](https://dart.dev/tools/linter-rules/use_null_aware_elements)
syntax.

This PR cleans up the remaining files not covered in the previous parts,
making the code more concise.

## Related PRs

- flutter#172198
- flutter#172306
- flutter#172307
- flutter#172322

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

<!--
Thanks for filing a pull request!
Reviewers are typically assigned within a week of filing a request.
To learn more about code review, see our documentation on Tree Hygiene:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
-->

Replace null checks with null aware elements - part 4

Part of flutter#172188

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

## Description

Continuing the work from @jamilsaadeh97 to replace verbose null checks
with modern
[null_aware_elements](https://dart.dev/tools/linter-rules/use_null_aware_elements)
syntax.

This PR cleans up the remaining files not covered in the previous parts,
making the code more concise.

## Related PRs

- flutter#172198
- flutter#172306
- flutter#172307
- flutter#172322

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

<!--
Thanks for filing a pull request!
Reviewers are typically assigned within a week of filing a request.
To learn more about code review, see our documentation on Tree Hygiene:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
-->

Replace null checks with null aware elements - part 4

Part of flutter#172188

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md