For a long time, `gfx_traits` has held a lot of things unrelated to graphics
and also unrelated to the `gfx` crate (which is mostly about fonts).
This is a cleanup which does a few things:
1. Move non `gfx` crate things out of `gfx_traits`. This is important in
order to prevent dependency cycles with a different integration between
layout, script, and fonts.
2. Rename the `msg` crate to `base`. It didn't really contain anything
to do with messages and instead mostly holds ids, which are used
across many different crates in Servo. This new crate will hold the
*rare* data types that are widely used.
Details:
- All BackgroundHangMonitor-related things from base to a new
`background_hang_monitor_api` crate.
- Moved `TraversalDirection` to `script_traits`
- Moved `Epoch`-related things from `gfx_traits` to `base`.
- Moved `PrintTree` to base. This should be widely useful in Servo.
- Moved `WebrenderApi` from `base` to `webrender_traits` and renamed it
to `WebRenderFontApi`.
Break the association between pipelines and browsing context actors.
Now there is one browsing context actor per actual browsing context,
and individual actors keep track of known pipelines as necessary.
There is also one console/performance/timeline/inspector/etc. actor
per browsing context.
This also centralizes more information in the browsing context actor.
Rather than duplicating state for the active pipeline in actors that
need to use it, each actor now remembers the name of its associated
browsing context actor and obtains that state whenever it's necessary.
The purpose of this is to fix how objects were previously evaluated in
the developer tools.
- Before this, evaluating an object such as the `window` would `panic!`
- After this, evaluating an object such as the `window` outputs `[object
Window]`
A few things to note:
- This commit contains `unsafe` code.
- This does not contain a test because the developer tools cannot be properly tested until #5971 lands.
