Implemented parseSingleValue in CSSPropertyAPICounterIncrement.

third_party/WebKit/Source/core/css/properties/CSSPropertyAPICounterIncrement.cpp

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/properties/CSSPropertyAPICounterIncrement.h"
 
-namespace blink {}  // namespace blink
+#include "core/css/properties/CSSPropertyCounterUtils.h"
+
+namespace blink {
+
+const CSSValue* CSSPropertyAPICounterIncrement::parseSingleValue(
+    CSSParserTokenRange& range,
+    const CSSParserContext&) {
+  return CSSPropertyCounterUtils::consumeCounter(
+      range, CSSPropertyCounterUtils::kIncrementDefaultValue);
+}
+
+}  // namespace blink