Bug 1507381 - Stop exposing moz-window-dragging to content r=firefox-style-system-reviewers,emilio

Differential Revision: https://phabricator.services.mozilla.com/D258712

Author: mr-cheffy

layout/style/test/property_database.js

@@ -9842,14 +9842,6 @@ var gCSSProperties = {
     other_values: ["non-scaling-stroke"],
     invalid_values: ["none non-scaling-stroke"],
   },
-  "-moz-window-dragging": {
-    domProp: "MozWindowDragging",
-    inherited: false,
-    type: CSS_TYPE_LONGHAND,
-    initial_values: ["default"],
-    other_values: ["drag", "no-drag"],
-    invalid_values: ["none"],
-  },
   "accent-color": {
     domProp: "accentColor",
     inherited: true,

layout/style/test/test_non_content_accessible_properties.html

@@ -11,6 +11,7 @@
   "-moz-window-transform",
   "-moz-default-appearance",
   "-moz-user-focus",
+  "-moz-window-dragging",
 ];
 
 const UA_ONLY_PROPERTIES = [

servo/components/style/properties/longhands/ui.mako.rs

@@ -39,14 +39,14 @@ ${helpers.predefined_type(
     affects="",
 )}
 
-// TODO(emilio): This probably should be hidden from content.
 ${helpers.single_keyword(
     "-moz-window-dragging",
     "default drag no-drag",
     engines="gecko",
     gecko_ffi_name="mWindowDragging",
     gecko_enum_prefix="StyleWindowDragging",
     animation_type="discrete",
+    enabled_in="chrome",
     spec="None (Nonstandard Firefox-only property)",
     affects="paint",
 )}