Auto merge of #16733 - KuoE0:bug-1356072, r=xidorn

Make stylo support moz-prefixed cursor values.

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This issue is reported at https://bugzilla.mozilla.org/show_bug.cgi?id=1356072.

We need to support the following moz-prefix properties in stylo:
- -moz-grab
- -moz-grabbing
- -moz-zoom-in
- -moz-zoom-out

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix [Bug 1356072](https://bugzilla.mozilla.org/show_bug.cgi?id=1356072).

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- [X] These changes do not require tests because the tests already exist in Gecko.

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components/style/Cargo.toml

@@ -13,7 +13,7 @@ path = "lib.rs"
 doctest = false
 
 [features]
-gecko = ["nsstring_vendor", "rayon/unstable", "num_cpus"]
+gecko = ["nsstring_vendor", "rayon/unstable", "num_cpus", "style_traits/gecko"]
 use_bindgen = ["bindgen", "regex"]
 servo = ["serde/unstable", "serde", "serde_derive", "heapsize", "heapsize_derive",
          "style_traits/servo", "servo_atoms", "servo_config", "html5ever",

components/style/properties/gecko.mako.rs

@@ -3978,6 +3978,11 @@ clip-path
                 Cursor::AllScroll => structs::NS_STYLE_CURSOR_ALL_SCROLL,
                 Cursor::ZoomIn => structs::NS_STYLE_CURSOR_ZOOM_IN,
                 Cursor::ZoomOut => structs::NS_STYLE_CURSOR_ZOOM_OUT,
+                // note: the following properties are gecko-only.
+                Cursor::MozGrab => structs::NS_STYLE_CURSOR_GRAB,
+                Cursor::MozGrabbing => structs::NS_STYLE_CURSOR_GRABBING,
+                Cursor::MozZoomIn => structs::NS_STYLE_CURSOR_ZOOM_IN,
+                Cursor::MozZoomOut => structs::NS_STYLE_CURSOR_ZOOM_OUT,
             }
         } as u8;