Auto merge of #12700 - jeenalee:jeena-requestAPI, r=jdm

Implement the Request API

<!-- Please describe your changes on the following line: -->
This PR implements the [Request API](https://fetch.spec.whatwg.org/#request-class) for the Fetch API, including its attributes and constructor, and introduces changes in relevant files.

This Request integrates `net_traits::request::Request` and `dom::headers`.

There are few related TODOs and comments:
1. `net_traits::request::Request`'s `headers` field does not point to `dom::request::Request`'s `headers_reflector`.
2. Every Constructor step that involves `Readable Stream` object is not implemented.
3. Every Constructor step that involves `entry settings object` or `environment settings object` is not implemented.
4. `./mach build -d` does not report any error, but prints a few warnings about unused variables related to (1) and (2).
5. Enum `ReferrerPolicy` generated by `RequestBinding` does not match `net_traits::request::Request`'s implementation.
6. `Promise`s in Body webidl are commented out.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #11895 (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests  because tests for the Request API already exists, but this commit does not implement the interface fully.

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

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components/net_traits/request.rs

@@ -10,7 +10,7 @@ use std::mem::swap;
 use url::{Origin as UrlOrigin, Url};
 
 /// An [initiator](https://fetch.spec.whatwg.org/#concept-request-initiator)
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum Initiator {
     None,
     Download,
@@ -20,14 +20,14 @@ pub enum Initiator {
 }
 
 /// A request [type](https://fetch.spec.whatwg.org/#concept-request-type)
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum Type {
     None, Audio, Font, Image,
     Script, Style, Track, Video
 }
 
 /// A request [destination](https://fetch.spec.whatwg.org/#concept-request-destination)
-#[derive(Copy, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Copy, Clone, PartialEq, Serialize, Deserialize, HeapSizeOf)]
 pub enum Destination {
     None, Document, Embed, Font, Image, Manifest,
     Media, Object, Report, Script, ServiceWorker,
@@ -35,14 +35,14 @@ pub enum Destination {
 }
 
 /// A request [origin](https://fetch.spec.whatwg.org/#concept-request-origin)
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, PartialEq, Debug, HeapSizeOf)]
 pub enum Origin {
     Client,
     Origin(UrlOrigin)
 }
 
 /// A [referer](https://fetch.spec.whatwg.org/#concept-request-referrer)
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, HeapSizeOf)]
 pub enum Referer {
     NoReferer,
     /// Default referer if nothing is specified
@@ -51,7 +51,7 @@ pub enum Referer {
 }
 
 /// A [request mode](https://fetch.spec.whatwg.org/#concept-request-mode)
-#[derive(Copy, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Copy, Clone, PartialEq, Serialize, Deserialize, HeapSizeOf)]
 pub enum RequestMode {
     Navigate,
     SameOrigin,
@@ -60,7 +60,7 @@ pub enum RequestMode {
 }
 
 /// Request [credentials mode](https://fetch.spec.whatwg.org/#concept-request-credentials-mode)
-#[derive(Copy, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Copy, Clone, PartialEq, Serialize, Deserialize, HeapSizeOf)]
 pub enum CredentialsMode {
     Omit,
     CredentialsSameOrigin,
@@ -68,7 +68,7 @@ pub enum CredentialsMode {
 }
 
 /// [Cache mode](https://fetch.spec.whatwg.org/#concept-request-cache-mode)
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum CacheMode {
     Default,
     NoStore,
@@ -79,7 +79,7 @@ pub enum CacheMode {
 }
 
 /// [Redirect mode](https://fetch.spec.whatwg.org/#concept-request-redirect-mode)
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum RedirectMode {
     Follow,
     Error,
@@ -87,7 +87,7 @@ pub enum RedirectMode {
 }
 
 /// [Response tainting](https://fetch.spec.whatwg.org/#concept-request-response-tainting)
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum ResponseTainting {
     Basic,
     CORSTainting,
@@ -95,7 +95,7 @@ pub enum ResponseTainting {
 }
 
 /// [Window](https://fetch.spec.whatwg.org/#concept-request-window)
-#[derive(Copy, Clone, PartialEq)]
+#[derive(Copy, Clone, PartialEq, HeapSizeOf)]
 pub enum Window {
     NoWindow,
     Client,
@@ -138,11 +138,13 @@ pub struct RequestInit {
 }
 
 /// A [Request](https://fetch.spec.whatwg.org/#requests) as defined by the Fetch spec
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct Request {
+    #[ignore_heap_size_of = "Defined in hyper"]
     pub method: RefCell<Method>,
     pub local_urls_only: bool,
     pub sandboxed_storage_area_urls: bool,
+    #[ignore_heap_size_of = "Defined in hyper"]
     pub headers: RefCell<Headers>,
     pub unsafe_request: bool,
     pub body: RefCell<Option<Vec<u8>>>,