Add referrer to navigation fetch request
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Implement step 13 of [following hyperlinks](https://html.spec.whatwg.org/#following-hyperlinks-2) and step 14.3 of [window open](https://html.spec.whatwg.org/#window-open-steps), as well as other referrer- and fetch-related updates.
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- [x] These changes fix#22890 (GitHub issue number if applicable)
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Magicleap package fixes
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A couple of fixes for magicleap packaging...
* Move the setting of the debuggable flag into the `.package` file where it belongs,
* Allow compiling with v0.20.0 of the SDK.
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Update SetCursor behavior
We were initially sending a SetCursor message on every mouse move because of a winit bug, which is now fixed.
Also, we had a layout SetCursor message that was never used.
Fix#18599
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Upgrade to rustc 1.36.0-nightly (e305df184 2019-04-24)
This includes a `size_of` regression for a few DOM types, due to https://github.com/rust-lang/rust/pull/58623 which replaces the implementation of `HashMap` in the standard library to Hashbrown.
Although `size_of<HashMap>` grows, it’s not obvious how total memory usage is going to be impacted: Hashbrown only has one `u8` instead of one `usize` of overhead per hash table bucket for storing (part of) a hash, and so might allocate less memory itself.
Hashbrown also typically has better run time performance: https://github.com/rust-lang/hashbrown#performance
Still, I’ve filed https://github.com/rust-lang/hashbrown/issues/69 about potentially reducing the `size_of<HashMap>` regression.
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This includes a `size_of` regression for a few DOM types,
due to https://github.com/rust-lang/rust/pull/58623 which replaces the
implementation of `HashMap` in the standard library to Hashbrown.
Although `size_of<HashMap>` grows, it’s not obvious how total memory usage
is going to be impacted: Hashbrown only has one `u8` instead of one `usize`
of overhead per hash table bucket for storing (part of) a hash,
and so might allocate less memory itself.
Hashbrown also typically has better run time performance:
https://github.com/rust-lang/hashbrown#performance
Still, I’ve filed https://github.com/rust-lang/hashbrown/issues/69
about potentially reducing the `size_of<HashMap>` regression.
