Auto merge of #424 - jrmuizel:sync-desc, r=emilio

Make CTFontDescriptor Send and Sync and expose attributes()

Author: bors-servo

core-text/src/font_descriptor.rs

@@ -194,6 +194,10 @@ declare_TCFType! {
 impl_TCFType!(CTFontDescriptor, CTFontDescriptorRef, CTFontDescriptorGetTypeID);
 impl_CFTypeDescription!(CTFontDescriptor);
 
+// "Font objects (CTFont, CTFontDescriptor, and associated objects) can be used
+//  simultaneously by multiple operations, work queues, or threads."
+unsafe impl Send for CTFontDescriptor {}
+unsafe impl Sync for CTFontDescriptor {}
 
 impl CTFontDescriptor {
     fn get_string_attribute(&self, attribute: CFStringRef) -> Option<String> {
@@ -289,6 +293,13 @@ impl CTFontDescriptor {
             Ok(CTFontDescriptor::wrap_under_create_rule(desc))
         }
     }
+
+    pub fn attributes(&self) -> CFDictionary<CFString, CFType> {
+        unsafe {
+            let attrs = CTFontDescriptorCopyAttributes(self.as_concrete_TypeRef());
+            CFDictionary::wrap_under_create_rule(attrs)
+        }
+    }
 }
 
 pub fn new_from_attributes(attributes: &CFDictionary<CFString, CFType>) -> CTFontDescriptor {