style: Rejigger a bit rust features so that rusttests still link.

We cannot compile with just feature(gecko + debug_assertions), since that's how
debug rusttests get compiled and they don't have the refcount logging stuff.

We were getting away with it for the pre-existing usage of the style crate,
because it wasn't used during any test and presumably the linker didn't
complain. But servo_arc is definitely used in tests.

Differential Revision: https://phabricator.services.mozilla.com/D32691

components/servo_arc/Cargo.toml

@@ -12,7 +12,7 @@ path = "lib.rs"
 
 [features]
 servo = ["serde"]
-gecko = []
+gecko_refcount_logging = []
 
 [dependencies]
 nodrop = {version = "0.1.8"}

components/servo_arc/lib.rs

@@ -177,7 +177,7 @@ impl<T> Arc<T> {
             data,
         }));
 
-        #[cfg(all(feature = "gecko", debug_assertions))]
+        #[cfg(feature = "gecko_refcount_logging")]
         unsafe {
             // FIXME(emilio): Would be so amazing to have
             // std::intrinsics::type_name() around, so that we could also report
@@ -312,7 +312,7 @@ impl<T: ?Sized> Arc<T> {
 
     #[inline(always)]
     fn record_drop(&self) {
-        #[cfg(all(feature = "gecko", debug_assertions))]
+        #[cfg(feature = "gecko_refcount_logging")]
         unsafe {
             NS_LogDtor(self.ptr() as *const _, b"ServoArc\0".as_ptr() as *const _, 8);
         }
@@ -348,7 +348,7 @@ impl<T: ?Sized> Arc<T> {
     }
 }
 
-#[cfg(all(feature = "gecko", debug_assertions))]
+#[cfg(feature = "gecko_refcount_logging")]
 extern "C" {
     fn NS_LogCtor(aPtr: *const std::os::raw::c_void, aTypeName: *const std::os::raw::c_char, aSize: u32);
     fn NS_LogDtor(aPtr: *const std::os::raw::c_void, aTypeName: *const std::os::raw::c_char, aSize: u32);
@@ -745,7 +745,7 @@ impl<H, T> Arc<HeaderSlice<H, [T]>> {
             );
         }
 
-        #[cfg(all(feature = "gecko", debug_assertions))]
+        #[cfg(feature = "gecko_refcount_logging")]
         unsafe {
             if !is_static {
                 // FIXME(emilio): Would be so amazing to have

components/style/Cargo.toml

@@ -22,6 +22,7 @@ servo = ["serde", "style_traits/servo", "servo_atoms", "servo_config", "html5eve
          "cssparser/serde", "encoding_rs", "malloc_size_of/servo", "arrayvec/use_union",
          "servo_url", "string_cache", "crossbeam-channel", "to_shmem/servo", "servo_arc/servo"]
 gecko_debug = []
+gecko_refcount_logging = []
 gecko_profiler = []
 
 [dependencies]

components/style/rule_tree/mod.rs

@@ -755,7 +755,7 @@ unsafe impl Sync for RuleTree {}
 unsafe impl Send for RuleTree {}
 
 // On Gecko builds, hook into the leak checking machinery.
-#[cfg(all(feature = "gecko", debug_assertions))]
+#[cfg(feature = "gecko_refcount_logging")]
 mod gecko_leak_checking {
     use super::RuleNode;
     use std::mem::size_of;
@@ -788,13 +788,13 @@ mod gecko_leak_checking {
 
 #[inline(always)]
 fn log_new(_ptr: *const RuleNode) {
-    #[cfg(all(feature = "gecko", debug_assertions))]
+    #[cfg(feature = "gecko_refcount_logging")]
     gecko_leak_checking::log_ctor(_ptr);
 }
 
 #[inline(always)]
 fn log_drop(_ptr: *const RuleNode) {
-    #[cfg(all(feature = "gecko", debug_assertions))]
+    #[cfg(feature = "gecko_refcount_logging")]
     gecko_leak_checking::log_dtor(_ptr);
 }