Relands https://github.com/flutter/flutter/pull/150808
The original version of the pr [accidentally deleted the back button](https://github.com/flutter/flutter/pull/150808#discussion_r1655444210), which didn't block the app building but made the test hang because it couldn't back out of the demo pages.
Repro-ed the failure, and then tested that
```
new_gallery_opengles_impeller__transition_perf
new_gallery__transition_perf
new_gallery_impeller_old_zoom__transition_perf
new_gallery__crane_perf
new_gallery_impeller__transition_perf
```
All pass on my pixel 7 pro, with ` dart bin/test_runner.dart test -t <test>`, after re-adding the mistakenly deleted content.
Did not test on an iOS device (I don't have one), but those tests were failing for the same reason from what I can tell:
```
> reply@study
[2024-06-26 12:49:21.884543] [STDOUT] stdout: [ ] scrolling to demo
[2024-06-26 12:49:22.412479] [STDOUT] stdout: [ +527 ms] tapping demo
[2024-06-26 12:49:28.075978] [STDOUT] stderr: [+5663 ms] VMServiceFlutterDriver: tap message is taking a long time to complete...
```
Which is the same error, and which makes sense - they got stuck because they couldn't back out of the page.
Sorry for the churn ð
Reverts: flutter/flutter#150808
Initiated by: gmackall
Reason for reverting: Causing the new_gallery tests to hang.
I can repro now though, so should be able to find a fix shortly
Original PR Author: gmackall
Reviewed By: {christopherfujino, johnmccutchan, jtmcdole, jonahwilliams}
This change reverts the following previous change:
Removes the `dual_screen` package from `new_gallery`. Unblocks the fourth attempt to land https://github.com/flutter/engine/pull/53001.
### fixes#136139
<br>
<details open> <summary><b>getting sentimental in the PR description</b> (click to collapse)<br><br></summary>
The past 7 months have been quite the journeyâI made some huge blunders and some huge accomplishmentsâa very fun time overall.
I really appreciate the people who took the time to perform code review for my refactoring shenanigans: **christopherfujino**, **andrewkolos**, **LongCatIsLooong**, **gspencergoog**, **loic-sharma**, **Piinks**, **bernaferrari**, **bartekpacia**, **bleroux**, **kevmoo**, **rakudrama**, **XilaiZhang**, **QuncCccccc**, **MominRaza**, and **victorsanni**.
And a huge shoutout to 2 individuals:
- @justinmc, for offering to sponsor me for commit access (words could not describe my excitement)
- @goderbauer, for being super duper proactive and consistent with code review
<br>
</details>
This pull request makes 13 "switch statements â switch expressions" PRs in total, reducing the LOC in this repo by **1,974**!
From now on, I'll make sure to request a test exemption for each refactoring PR ð
PR #147801 introduced some convenient `AnimationStatus` getters, but I just realized that `AnimationController` now has 2 getters for the same thing: `isAnimating` and `isRunning`.
The intent of this pull request is to correct that mistake, and implement the getters in the appropriate places.
This PR is step 12 in the journey to solve issue #136139 and make the
entire Flutter repo more readable.
Most of it involves implementing switch expressions, and there's also a
few other random things that I wanted to clean up a bit.
Some cause of jank on both Skia and Impeller are these massive images. We should just resize them so that the noise is reduced and we can see other performance issues.
Fixes https://github.com/flutter/flutter/issues/147797
Tested: this is a test!
Here's another PR with a couple of typos fixed. As you can see there was a typo in _fileReferenceI**n**dentifiers_, in class _ParsedProjectInfo._ Maybe we should do some check on that since I'm not sure if that property is used somewhere outside Flutter?
This pull request aims for improved readability, based on issue #146600.
```dart
// before
Set<Color> _distinctVisibleColors() {
final Set<Color> distinctVisibleColors = <Color>{};
if (top.style != BorderStyle.none) {
distinctVisibleColors.add(top.color);
}
if (right.style != BorderStyle.none) {
distinctVisibleColors.add(right.color);
}
if (bottom.style != BorderStyle.none) {
distinctVisibleColors.add(bottom.color);
}
if (left.style != BorderStyle.none) {
distinctVisibleColors.add(left.color);
}
return distinctVisibleColors;
}
// after
Set<Color> _distinctVisibleColors() {
return <Color>{
if (top.style != BorderStyle.none) top.color,
if (right.style != BorderStyle.none) right.color,
if (bottom.style != BorderStyle.none) bottom.color,
if (left.style != BorderStyle.none) left.color,
};
}
```
Most of the repo should be covered in this PR (aside from `flutter_tools/`, since there was a lot going on in there).
Fixes https://github.com/flutter/flutter/issues/143482
This brings in the gallery more or less as is:
* Removed localizations
* Ensure tests still run (locally verified, will switch CI later).
* Removed deferred components
* Fixup pubspec