style: Support css use counters for unimplemented properties.

For developing properties, we will handle them in an other bug.

Besides, I use an iframe for the test because we create a use counter in
the constructor of Document, which use the prefs to decide what kind of
properties we want to record. So, in the test, we have to reload iframe
to make sure we re-create the document, so does the use counter, to make
sure the prefs work properly.

The two prefs affect the css use counters:
1. layout.css.use-counters.enabled: Allocate use counters, and record
   non-custom properties.
2. layout.css.use-counters-unimplemented.enabled: Record all unimplmented
   properties into the use counters.

If we disable layout.css.use-counters.enblaed, we don't create use counters
object, so layout.css.use-counters-unimplemented.enabled doesn't work,
either.

Differential Revision: https://phabricator.services.mozilla.com/D43860

components/style/use_counters/mod.rs

@@ -6,6 +6,7 @@
 
 #[cfg(feature = "gecko")]
 use crate::gecko_bindings::sugar::ownership::{HasBoxFFI, HasFFI, HasSimpleFFI};
+use crate::properties::{CountedUnknownProperty, COUNTED_UNKNOWN_PROPERTY_COUNT};
 use crate::properties::{NonCustomPropertyId, NON_CUSTOM_PROPERTY_ID_COUNT};
 use std::cell::Cell;
 
@@ -15,46 +16,62 @@ const BITS_PER_ENTRY: usize = 64;
 #[cfg(target_pointer_width = "32")]
 const BITS_PER_ENTRY: usize = 32;
 
+/// One bit per each non-custom CSS property.
+#[derive(Default)]
+pub struct CountedUnknownPropertyUseCounters {
+    storage: [Cell<usize>; (COUNTED_UNKNOWN_PROPERTY_COUNT - 1 + BITS_PER_ENTRY) / BITS_PER_ENTRY],
+}
+
 /// One bit per each non-custom CSS property.
 #[derive(Default)]
 pub struct NonCustomPropertyUseCounters {
     storage: [Cell<usize>; (NON_CUSTOM_PROPERTY_ID_COUNT - 1 + BITS_PER_ENTRY) / BITS_PER_ENTRY],
 }
 
-impl NonCustomPropertyUseCounters {
-    /// Returns the bucket a given property belongs in, and the bitmask for that
-    /// property.
-    #[inline(always)]
-    fn bucket_and_pattern(id: NonCustomPropertyId) -> (usize, usize) {
-        let bit = id.bit();
-        let bucket = bit / BITS_PER_ENTRY;
-        let bit_in_bucket = bit % BITS_PER_ENTRY;
-        (bucket, 1 << bit_in_bucket)
-    }
-
-    /// Record that a given non-custom property ID has been parsed.
-    #[inline]
-    pub fn record(&self, id: NonCustomPropertyId) {
-        let (bucket, pattern) = Self::bucket_and_pattern(id);
-        let bucket = &self.storage[bucket];
-        bucket.set(bucket.get() | pattern)
-    }
-
-    /// Returns whether a given non-custom property ID has been recorded
-    /// earlier.
-    #[inline]
-    pub fn recorded(&self, id: NonCustomPropertyId) -> bool {
-        let (bucket, pattern) = Self::bucket_and_pattern(id);
-        self.storage[bucket].get() & pattern != 0
-    }
-
-    /// Merge `other` into `self`.
-    #[inline]
-    fn merge(&self, other: &Self) {
-        for (bucket, other_bucket) in self.storage.iter().zip(other.storage.iter()) {
-            bucket.set(bucket.get() | other_bucket.get())
+macro_rules! property_use_counters_methods {
+    ($id: ident) => {
+        /// Returns the bucket a given property belongs in, and the bitmask for that
+        /// property.
+        #[inline(always)]
+        fn bucket_and_pattern(id: $id) -> (usize, usize) {
+            let bit = id.bit();
+            let bucket = bit / BITS_PER_ENTRY;
+            let bit_in_bucket = bit % BITS_PER_ENTRY;
+            (bucket, 1 << bit_in_bucket)
         }
-    }
+
+        /// Record that a given property ID has been parsed.
+        #[inline]
+        pub fn record(&self, id: $id) {
+            let (bucket, pattern) = Self::bucket_and_pattern(id);
+            let bucket = &self.storage[bucket];
+            bucket.set(bucket.get() | pattern)
+        }
+
+        /// Returns whether a given property ID has been recorded
+        /// earlier.
+        #[inline]
+        pub fn recorded(&self, id: $id) -> bool {
+            let (bucket, pattern) = Self::bucket_and_pattern(id);
+            self.storage[bucket].get() & pattern != 0
+        }
+
+        /// Merge `other` into `self`.
+        #[inline]
+        fn merge(&self, other: &Self) {
+            for (bucket, other_bucket) in self.storage.iter().zip(other.storage.iter()) {
+                bucket.set(bucket.get() | other_bucket.get())
+            }
+        }
+    };
+}
+
+impl CountedUnknownPropertyUseCounters {
+    property_use_counters_methods!(CountedUnknownProperty);
+}
+
+impl NonCustomPropertyUseCounters {
+    property_use_counters_methods!(NonCustomPropertyId);
 }
 
 /// The use-counter data related to a given document we want to store.
@@ -63,6 +80,8 @@ pub struct UseCounters {
     /// The counters for non-custom properties that have been parsed in the
     /// document's stylesheets.
     pub non_custom_properties: NonCustomPropertyUseCounters,
+    /// The counters for css properties which we haven't implemented yet.
+    pub counted_unknown_properties: CountedUnknownPropertyUseCounters,
 }
 
 impl UseCounters {
@@ -72,7 +91,9 @@ impl UseCounters {
     #[inline]
     pub fn merge(&self, other: &Self) {
         self.non_custom_properties
-            .merge(&other.non_custom_properties)
+            .merge(&other.non_custom_properties);
+        self.counted_unknown_properties
+            .merge(&other.counted_unknown_properties);
     }
 }