Use line comments instead of block comments
as block comments contain trailing whitespace
after formatting with rustfmt.
Skip tests for malloc_size_of and script_plugins
with rustfmt as they have many block comments.
Add lots of derived Debug impls
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Add a bunch of derived `Debug` impls. After this, pretty much anything that implements `Deserializable` also implements `Debug`. The exception is `webrender_api::RenderApiSender`, which would need a webrender PR.
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- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because it's just debugging
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We had a mix of 0.6.2 and 0.6.5 (which is the current release),
this unifies to the latest version. It also enables the union
feature which removes the discriminant, reducing memory usage.
Before this change, if we needed to create a Font which we've already
created, but at a new size, then we'd fetch the FontTemplateInfo again.
If the bytes of the font are held in memory, then this could be
expensive as we need to pass those bytes over IPC.
FontTemplateData gets passed over IPC during the communication between
FontContext and FontCacheThread. Serializing and deserializing these
bytes is expensive, so this change ensures that we only do that when the
bytes can't be read from disk. A similar strategy is already used on
macos and windows.
The performance problem was particularly noticeable after implenting
font fallback, where the content process would potentially work through
a list of fonts, trying to find one which contains a certain glyph. That
could result in lots of font bytes going over IPC.
