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This PR adds dom::Response and dom::Request's `Text()`, `Blob()`, `Json()`, and (part of the) `FormData()` functions, part of the [Body mixin](https://fetch.spec.whatwg.org/#body). The corresponding tests have also been updated as passing.
@jeenalee also contributed to this PR, primarily the `Blob()`, `Json()`, and `FormData()` implementations.
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Source-Repo: https://github.com/servo/servo
Source-Revision: a03a5e814a7003ba9697aa37d7492cf9e6425ea4
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This PR adds the [dom::Response](https://fetch.spec.whatwg.org/#response-class) implementation and addresses #11896.
The relevant passing tests` expectations have been updated.
In order to allow non-UTF-8-encoded status messages, `net_traits::response::Response`'s `raw_status` field has been changed from type [`Option<RawStatus>`](https://doc.servo.org/hyper/http/struct.RawStatus.html) to type `Option<(u16, Vec<u8>)>`. As a result, a few other files which rely on the `raw_status` field were affected and updated.
TODOs:
- The `body` and `trailer` methods. Relies on implementation of `ReadableStream` and `Promise`s.
- Similarly, replace the dummy constructor `_body: Option<USVString>` argument with `body: ResponseBodyInit`.
- Currently, whenever `r's response's header list` or `r's Headers object` are mentioned, I always modify the `headers_reflector` field (of type dom::Headers, or `r's Headers object`) and not the corresponding hyper::Headers list in the net_traits::Response field. A completely accurate interpretation of the spec might consider making both of these lists the same thing via a reference. [Discussion](https://github.com/whatwg/fetch/issues/358) was [had](https://github.com/servo/servo/pull/12884).
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Source-Repo: https://github.com/servo/servo
Source-Revision: 5a5a76cc5db830d2e622d4e0924837383b64dfa2
