servo: Merge #17901 - style: Remove now-unused empty Variables struct (from heycam:rm-empty-variables); r=emilio

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The `Servo_GetEmptyVariables` FFI function no longer has any callers from Gecko, so we can remove it and the code that creates/frees that struct.

---
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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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Source-Repo: https://github.com/servo/servo
Source-Revision: e95da98f5fae9705131dd0731679241b295095dd

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 477bbed9e1dea773c06fdff4b38af783ae73201b

servo/components/style/gecko/generated/bindings.rs

@@ -2866,9 +2866,6 @@ extern "C" {
                                          index: u32, name: *mut nsAString)
      -> bool;
 }
-extern "C" {
-    pub fn Servo_GetEmptyVariables() -> *const nsStyleVariables;
-}
 extern "C" {
     pub fn Gecko_CreateCSSErrorReporter(sheet: *mut ServoStyleSheet,
                                         loader: *mut Loader, uri: *mut nsIURI)

servo/components/style/properties/gecko.mako.rs

@@ -19,13 +19,11 @@ use gecko_bindings::bindings::Gecko_Construct_Default_${style_struct.gecko_ffi_n
 use gecko_bindings::bindings::Gecko_CopyConstruct_${style_struct.gecko_ffi_name};
 use gecko_bindings::bindings::Gecko_Destroy_${style_struct.gecko_ffi_name};
 % endfor
-use gecko_bindings::bindings::Gecko_Construct_nsStyleVariables;
 use gecko_bindings::bindings::Gecko_CopyCounterStyle;
 use gecko_bindings::bindings::Gecko_CopyCursorArrayFrom;
 use gecko_bindings::bindings::Gecko_CopyFontFamilyFrom;
 use gecko_bindings::bindings::Gecko_CopyImageValueFrom;
 use gecko_bindings::bindings::Gecko_CopyListStyleImageFrom;
-use gecko_bindings::bindings::Gecko_Destroy_nsStyleVariables;
 use gecko_bindings::bindings::Gecko_EnsureImageLayersLength;
 use gecko_bindings::bindings::Gecko_FontFamilyList_AppendGeneric;
 use gecko_bindings::bindings::Gecko_FontFamilyList_AppendNamed;
@@ -43,7 +41,6 @@ use gecko_bindings::bindings::{Gecko_ResetFilters, Gecko_CopyFiltersFrom};
 use gecko_bindings::bindings::RawGeckoPresContextBorrowed;
 use gecko_bindings::structs;
 use gecko_bindings::structs::nsCSSPropertyID;
-use gecko_bindings::structs::nsStyleVariables;
 use gecko_bindings::sugar::ns_style_coord::{CoordDataValue, CoordData, CoordDataMut};
 use gecko::values::convert_nscolor_to_rgba;
 use gecko::values::convert_rgba_to_nscolor;
@@ -5030,26 +5027,3 @@ ${impl_style_struct(style_struct)}
 <%self:raw_impl_trait style_struct="${style_struct}"></%self:raw_impl_trait>
 % endif
 % endfor
-
-// This is only accessed from the Gecko main thread.
-static mut EMPTY_VARIABLES_STRUCT: Option<nsStyleVariables> = None;
-
-#[no_mangle]
-#[allow(non_snake_case)]
-pub unsafe extern "C" fn Servo_GetEmptyVariables()
-                                                 -> *const nsStyleVariables {
-    EMPTY_VARIABLES_STRUCT.as_ref().unwrap()
-}
-
-pub fn initialize() {
-    unsafe {
-        EMPTY_VARIABLES_STRUCT = Some(zeroed());
-        Gecko_Construct_nsStyleVariables(EMPTY_VARIABLES_STRUCT.as_mut().unwrap());
-    }
-}
-
-pub fn shutdown() {
-    unsafe {
-        EMPTY_VARIABLES_STRUCT.take().as_mut().map(|v| Gecko_Destroy_nsStyleVariables(v));
-    }
-}

servo/ports/geckolib/glue.rs

@@ -90,7 +90,7 @@ use style::gecko_bindings::structs::nsresult;
 use style::gecko_bindings::sugar::ownership::{FFIArcHelpers, HasFFI, HasArcFFI, HasBoxFFI};
 use style::gecko_bindings::sugar::ownership::{HasSimpleFFI, Strong};
 use style::gecko_bindings::sugar::refptr::RefPtr;
-use style::gecko_properties::{self, style_structs};
+use style::gecko_properties::style_structs;
 use style::invalidation::element::restyle_hints::{self, RestyleHint};
 use style::media_queries::{MediaList, parse_media_query_list};
 use style::parallel;
@@ -158,18 +158,12 @@ pub extern "C" fn Servo_Initialize(dummy_url_data: *mut URLExtraData) {
     parser::assert_parsing_mode_match();
     traversal_flags::assert_traversal_flags_match();
 
-    // Initialize some static data.
-    gecko_properties::initialize();
-
     // Initialize the dummy url data
     unsafe { DUMMY_URL_DATA = dummy_url_data; }
 }
 
 #[no_mangle]
 pub extern "C" fn Servo_Shutdown() {
-    // Clear some static data to avoid shutdown leaks.
-    gecko_properties::shutdown();
-
     // The dummy url will be released after shutdown, so clear the
     // reference to avoid use-after-free.
     unsafe { DUMMY_URL_DATA = ptr::null_mut(); }

servo/tests/unit/stylo/check_bindings.py

@@ -24,10 +24,7 @@ with open(INPUT_FILE, "r") as bindings, open(OUTPUT_FILE, "w+") as tests:
 
     for line in bindings:
         match = pattern.search(line)
-
-        # GetStyleVariables is a Servo_* function, but temporarily defined on
-        # the gecko side
-        if match and match.group(1) != "GetStyleVariables":
+        if match:
             tests.write(TEMPLATE.format(name=match.group(1)))
 
     tests.write("}\n")