--- a/devtools/shared/css/generated/properties-db.js
+++ b/devtools/shared/css/generated/properties-db.js
@@ -5251,28 +5251,30 @@ exports.CSS_PROPERTIES = {
     "isInherited": false,
     "subproperties": [
       "counter-increment"
     ],
     "supports": [],
     "values": [
       "inherit",
       "initial",
+      "none",
       "unset"
     ]
   },
   "counter-reset": {
     "isInherited": false,
     "subproperties": [
       "counter-reset"
     ],
     "supports": [],
     "values": [
       "inherit",
       "initial",
+      "none",
       "unset"
     ]
   },
   "cursor": {
     "isInherited": true,
     "subproperties": [
       "cursor"
     ],

--- a/layout/inspector/tests/test_bug877690.html
+++ b/layout/inspector/tests/test_bug877690.html
@@ -217,16 +217,23 @@ function do_test() {
   var expected = [ "inherit", "initial", "unset" ];
   ok(testValues(values, expected), "property all's values.");
 
   var prop = "quotes"
   var values = InspectorUtils.getCSSValuesForProperty(prop);
   var expected = [ "inherit", "initial", "unset", "none" ];
   ok(testValues(values, expected), "property quotes's values.");
 
+  // Regression test for bug 1255384.
+  for (prop of ["counter-increment", "counter-reset"]) {
+    var values = InspectorUtils.getCSSValuesForProperty(prop);
+    var expected = [ "inherit", "initial", "unset", "none" ];
+    ok(testValues(values, expected), "property " + prop + "'s values.");
+  }
+
   SimpleTest.finish();
 }
 
 SimpleTest.waitForExplicitFinish();
 addLoadEvent(do_test);
 
 </script>
 </head>

--- a/layout/style/nsCSSPropList.h
+++ b/layout/style/nsCSSPropList.h
@@ -1647,27 +1647,27 @@ CSS_PROP_TEXT(
     eStyleAnimType_None)
 #endif // CSS_PROP_LIST_EXCLUDE_INTERNAL
 CSS_PROP_CONTENT(
     counter-increment,
     counter_increment,
     CounterIncrement,
     CSS_PROPERTY_PARSE_FUNCTION,
     "",
-    0,
+    VARIANT_INHERIT | VARIANT_NONE,
     nullptr,
     CSS_PROP_NO_OFFSET,
     eStyleAnimType_Discrete) // XXX bug 137285
 CSS_PROP_CONTENT(
     counter-reset,
     counter_reset,
     CounterReset,
     CSS_PROPERTY_PARSE_FUNCTION,
     "",
-    0,
+    VARIANT_INHERIT | VARIANT_NONE,
     nullptr,
     CSS_PROP_NO_OFFSET,
     eStyleAnimType_Discrete) // XXX bug 137285
 CSS_PROP_USERINTERFACE(
     cursor,
     cursor,
     Cursor,
     CSS_PROPERTY_PARSE_FUNCTION |