Tong Mu d3bbe5cb8a [macOS] Change view ID to signed (flutter/engine#39958)
This PR makes view ID signed from unsigned int64.

Initially, I made view IDs unsigned because they were opaque anyway. As
I'm working deeper into multiview, I found some issues that made me
think signed is better:

* Unsigned integers are worse
  * Sometimes you want negative values to represent special values.
* Unsigned integers are dangerous (if compared with signed ones by
mistake.)
* Unsigned integers are not needed
  * We're very unlikely to reach that big anyway.
  * Almost all other languages support only signed integers.
  * Also JavaScript only supports up to 51 bits of integer.

Therefore I think it's better to change them to signed int64, especially
before these APIs are widely used by developers.

## Pre-launch Checklist

- [ ] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [ ] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [ ] I read and followed the [Flutter Style Guide] and the [C++,
Objective-C, Java style guides].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I added new tests to check the change I am making or feature I am
adding, or Hixie said the PR is test-exempt. See [testing the engine]
for instructions on writing and running engine tests.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I signed the [CLA].
- [ ] 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/wiki/Tree-hygiene#overview
[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[C++, Objective-C, Java style guides]:
https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
[testing the engine]:
https://github.com/flutter/flutter/wiki/Testing-the-engine
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/wiki/Chat
2023-03-31 12:11:49 -07:00
..