Response API
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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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make nodeList iterable
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Not sure what to test in the script.
Need some advice. o_O
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Implement HTMLDataElement#value
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Implement HTMLDataElement#value
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- Reworked the append method to support the inner `hyper::header::Headers`'s HashMap `insert` method, which overwrites entries instead of appending.
- Filled out constructor as well as delete, get, has, and set methods.
- Updated relevant test expectations
Special-case setting location.hash to the empty string
This avoids endless redirect loops on facebook and makes us compliant with https://github.com/whatwg/html/pull/1318.
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Added checks that selection is valid, and fix set_selection_range.
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Fixed range checking for text inputs. Included some `debug_assert!` statements to check that the selection range is always valid.
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see #10947
Node::scroll_area should check if the element is potentially scrollable
Three tests use `document.scrollingElement` which was not supported at
the time of writing. They are, hence, expected to FAIL.
The last expected FAIL should be fixed by #10947.
Edited some comments, message texts.
indexed getter of form elements
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Added tests for cross-origin iframe parentage.
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Added (currently failing) tests for cross-origin iframe parentage.
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Make fetch happen
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Moves XHR over to the fetch backend.
Previous PR: https://github.com/servo/servo/pull/114
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