Added CSSPropertyBackgroundComponentUtils which holds background component parsing methods.

third_party/WebKit/Source/core/css/properties/CSSPropertyBackgroundComponentUtils.h

+// 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.
+
+#ifndef CSSPropertyBackgroundComponentUtils_h
+#define CSSPropertyBackgroundComponentUtils_h
+
+#include "core/CSSPropertyNames.h"
+#include "core/css/parser/CSSParserContext.h"
+
+#include "wtf/Allocator.h"
+
+namespace blink {
+
+class CSSParserTokenRange;
+class CSSValue;
+
+class CSSPropertyBackgroundComponentUtils {
+  STATIC_ONLY(CSSPropertyBackgroundComponentUtils);
+
+  static CSSValue* consumeBackgroundSize(CSSPropertyID unresolvedProperty,
+                                         CSSParserTokenRange&,
+                                         CSSParserMode);
+
+  static void addBackgroundValue(CSSValue*& list, CSSValue*);
+
+  static CSSValue* consumeBackgroundComponent(CSSPropertyID unresolvedProperty,
+                                              CSSParserTokenRange&,
+                                              const CSSParserContext*);
+};
+
+}  // namespace blink
+
+#endif  // CSSPropertyBackgroundComponentUtils_h