Add usage counter for each value of webkit-user-modify

third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp

Index: third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
index 39891d56d9ba28956a75004880692cdf714c4e80..1f6cb3feb3f0e13c068221094bd7277fde26d705 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
@@ -2323,6 +2323,24 @@ static void countKeywordOnlyPropertyUsage(CSSPropertyID property,
       break;
     }
 
+    case CSSPropertyWebkitUserModify: {
+      switch (valueID) {
+        case CSSValueReadOnly:
+          context->useCounter()->count(UseCounter::CSSValueUserModifyReadOnly);
+          break;
+        case CSSValueReadWrite:
+          context->useCounter()->count(UseCounter::CSSValueUserModifyReadWrite);
+          break;
+        case CSSValueReadWritePlaintextOnly:
+          context->useCounter()->count(
+              UseCounter::CSSValueUserModifyReadWritePlaintextOnly);
+          break;
+        default:
+          NOTREACHED();
+      }
+      break;
+    }
+
     default:
       break;
   }