Auto merge of #17123 - KuoE0:bug-1358993, r=heycam

Store the pointer of reusable sheets in StylesheetLoader.

<!-- Please describe your changes on the following line: -->

To make stylo support reusable style sheets, we need to store the pointer of reusable style sheets we got from gecko. And we pass them back to gecko to reuse.

---
<!-- 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 [Bug 1358993](https://bugzilla.mozilla.org/show_bug.cgi?id=1358993).

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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because the test cases are in Gecko.

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components/style/gecko/generated/bindings.rs

@@ -201,6 +201,7 @@ use gecko_bindings::structs::nscolor;
 use gecko_bindings::structs::nscoord;
 use gecko_bindings::structs::nsresult;
 use gecko_bindings::structs::Loader;
+use gecko_bindings::structs::LoaderReusableStyleSheets;
 use gecko_bindings::structs::ServoStyleSheet;
 use gecko_bindings::structs::EffectCompositor_CascadeLevel;
 use gecko_bindings::structs::UpdateAnimationsTasks;
@@ -540,6 +541,8 @@ extern "C" {
 extern "C" {
     pub fn Gecko_LoadStyleSheet(loader: *mut Loader,
                                 parent: *mut ServoStyleSheet,
+                                reusable_sheets:
+                                    *mut LoaderReusableStyleSheets,
                                 child_sheet: RawServoStyleSheetBorrowed,
                                 base_url_data: *mut RawGeckoURLExtraData,
                                 url_bytes: *const u8, url_length: u32,
@@ -1769,7 +1772,9 @@ extern "C" {
                                            data: *const nsACString,
                                            extra_data:
                                                *mut RawGeckoURLExtraData,
-                                           line_number_offset: u32);
+                                           line_number_offset: u32,
+                                           reusable_sheets:
+                                               *mut LoaderReusableStyleSheets);
 }
 extern "C" {
     pub fn Servo_StyleSheet_HasRules(sheet: RawServoStyleSheetBorrowed)
@@ -1799,6 +1804,10 @@ extern "C" {
 extern "C" {
     pub fn Servo_StyleSet_RebuildData(set: RawServoStyleSetBorrowed);
 }
+extern "C" {
+    pub fn Servo_StyleSet_MediumFeaturesChanged(set: RawServoStyleSetBorrowed)
+     -> bool;
+}
 extern "C" {
     pub fn Servo_StyleSet_AppendStyleSheet(set: RawServoStyleSetBorrowed,
                                            sheet: RawServoStyleSheetBorrowed,

ports/geckolib/glue.rs

@@ -65,12 +65,12 @@ use style::gecko_bindings::bindings::nsTimingFunctionBorrowed;
 use style::gecko_bindings::bindings::nsTimingFunctionBorrowedMut;
 use style::gecko_bindings::structs;
 use style::gecko_bindings::structs::{CSSPseudoElementType, CompositeOperation};
+use style::gecko_bindings::structs::{Loader, LoaderReusableStyleSheets};
 use style::gecko_bindings::structs::{RawServoStyleRule, ServoStyleSheet};
 use style::gecko_bindings::structs::{SheetParsingMode, nsIAtom, nsCSSPropertyID};
 use style::gecko_bindings::structs::{nsCSSFontFaceRule, nsCSSCounterStyleRule};
 use style::gecko_bindings::structs::{nsRestyleHint, nsChangeHint, PropertyValuePair};
 use style::gecko_bindings::structs::IterationCompositeOperation;
-use style::gecko_bindings::structs::Loader;
 use style::gecko_bindings::structs::MallocSizeOf;
 use style::gecko_bindings::structs::RawGeckoPresContextOwned;
 use style::gecko_bindings::structs::ServoElementSnapshotTable;
@@ -721,7 +721,7 @@ pub extern "C" fn Servo_StyleSheet_FromUTF8Bytes(loader: *mut Loader,
     let loader = if loader.is_null() {
         None
     } else {
-        Some(StylesheetLoader::new(loader, stylesheet))
+        Some(StylesheetLoader::new(loader, stylesheet, ptr::null_mut()))
     };
 
     // FIXME(emilio): loader.as_ref() doesn't typecheck for some reason?
@@ -750,7 +750,8 @@ pub extern "C" fn Servo_StyleSheet_ClearAndUpdate(stylesheet: RawServoStyleSheet
                                                   gecko_stylesheet: *mut ServoStyleSheet,
                                                   data: *const nsACString,
                                                   extra_data: *mut URLExtraData,
-                                                  line_number_offset: u32)
+                                                  line_number_offset: u32,
+                                                  reusable_sheets: *mut LoaderReusableStyleSheets)
 {
     let input = unsafe { data.as_ref().unwrap().as_str_unchecked() };
     let url_data = unsafe { RefPtr::from_ptr_ref(&extra_data) };
@@ -758,7 +759,7 @@ pub extern "C" fn Servo_StyleSheet_ClearAndUpdate(stylesheet: RawServoStyleSheet
     let loader = if loader.is_null() {
         None
     } else {
-        Some(StylesheetLoader::new(loader, gecko_stylesheet))
+        Some(StylesheetLoader::new(loader, gecko_stylesheet, reusable_sheets))
     };
 
     // FIXME(emilio): loader.as_ref() doesn't typecheck for some reason?
@@ -950,7 +951,7 @@ pub extern "C" fn Servo_CssRules_InsertRule(rules: ServoCssRulesBorrowed,
     let loader = if loader.is_null() {
         None
     } else {
-        Some(StylesheetLoader::new(loader, gecko_stylesheet))
+        Some(StylesheetLoader::new(loader, gecko_stylesheet, ptr::null_mut()))
     };
     let loader = loader.as_ref().map(|loader| loader as &StyleStylesheetLoader);
     let rule = unsafe { rule.as_ref().unwrap().as_str_unchecked() };

ports/geckolib/stylesheet_loader.rs

@@ -3,18 +3,20 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use style::gecko_bindings::bindings::Gecko_LoadStyleSheet;
-use style::gecko_bindings::structs::{Loader, ServoStyleSheet};
+use style::gecko_bindings::structs::{Loader, ServoStyleSheet, LoaderReusableStyleSheets};
 use style::gecko_bindings::sugar::ownership::{HasArcFFI, FFIArcHelpers};
 use style::media_queries::MediaList;
 use style::shared_lock::Locked;
 use style::stylearc::Arc;
 use style::stylesheets::{ImportRule, Stylesheet, StylesheetLoader as StyleStylesheetLoader};
 
-pub struct StylesheetLoader(*mut Loader, *mut ServoStyleSheet);
+pub struct StylesheetLoader(*mut Loader, *mut ServoStyleSheet, *mut LoaderReusableStyleSheets);
 
 impl StylesheetLoader {
-    pub fn new(loader: *mut Loader, parent: *mut ServoStyleSheet) -> Self {
-        StylesheetLoader(loader, parent)
+    pub fn new(loader: *mut Loader,
+               parent: *mut ServoStyleSheet,
+               reusable_sheets: *mut LoaderReusableStyleSheets) -> Self {
+        StylesheetLoader(loader, parent, reusable_sheets)
     }
 }
 
@@ -37,6 +39,7 @@ impl StyleStylesheetLoader for StylesheetLoader {
         unsafe {
             Gecko_LoadStyleSheet(self.0,
                                  self.1,
+                                 self.2,
                                  Stylesheet::arc_as_borrowed(&import.stylesheet),
                                  base_url_data,
                                  spec_bytes,