Auto merge of #17565 - cynicaldevil:new-parser-thread, r=nox,jdm

Servo's async Tokenizer: New! Improved! Now with multithreading!

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The Tokenizer, defined in the file `async_html.rs` will run on the main thread, while h5e's `Tokenizer`(along with its Sink) lives on the parser thread. Both h5e's `Tokenizer` and `Sink` communicate with the main thread Tokenizer via their own mpsc channels. The Sink keeps sending parser operations to the main thread, to be executed. For some operations, it waits for a message from the main thread before returning.

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- [ ] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/selectors/Cargo.toml

@@ -26,6 +26,8 @@ unstable = []
 bitflags = "0.7"
 matches = "0.1"
 cssparser = "0.18"
+heapsize = "0.4"
+heapsize_derive = "0.1"
 log = "0.3"
 fnv = "1.0"
 phf = "0.7.18"

components/selectors/context.rs

@@ -48,7 +48,7 @@ pub enum VisitedHandlingMode {
 /// Which quirks mode is this document in.
 ///
 /// See: https://quirks.spec.whatwg.org/
-#[derive(PartialEq, Eq, Copy, Clone, Hash, Debug)]
+#[derive(PartialEq, Eq, Copy, Clone, Hash, Debug, HeapSizeOf)]
 pub enum QuirksMode {
     /// Quirks mode.
     Quirks,

components/selectors/lib.rs

@@ -7,9 +7,11 @@
 
 #[macro_use] extern crate bitflags;
 #[macro_use] extern crate cssparser;
+#[macro_use] extern crate heapsize_derive;
 #[macro_use] extern crate log;
 #[macro_use] extern crate matches;
 extern crate fnv;
+extern crate heapsize;
 extern crate phf;
 extern crate precomputed_hash;
 #[cfg(test)] #[macro_use] extern crate size_of_test;