Implements CSSPropertyAPI for the -webkit-border-[start|end|before|after]-width properties.

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

Index: third_party/WebKit/Source/core/css/properties/CSSPropertyWebkitBorderWidthUtils.h
diff --git a/third_party/WebKit/Source/core/css/properties/CSSPropertyWebkitBorderWidthUtils.h b/third_party/WebKit/Source/core/css/properties/CSSPropertyWebkitBorderWidthUtils.h
new file mode 100644
index 0000000000000000000000000000000000000000..264a0231b3822c8db8756bf7d7558576959affce
--- /dev/null
+++ b/third_party/WebKit/Source/core/css/properties/CSSPropertyWebkitBorderWidthUtils.h
@@ -0,0 +1,23 @@
+// 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 CSSPropertyWebkitBorderWidthUtils_h
+#define CSSPropertyWebkitBorderWidthUtils_h
+
+#include "core/css/parser/CSSPropertyParserHelpers.h"
+#include "platform/wtf/Allocator.h"
+
+namespace blink {
+
+class CSSPropertyWebkitBorderWidthUtils {
+  STATIC_ONLY(CSSPropertyWebkitBorderWidthUtils);
+
+  static CSSValue* ConsumeBorderWidth(CSSParserTokenRange&,
+                                      CSSParserMode,
+                                      CSSPropertyParserHelpers::UnitlessQuirk);
+};
+
+}  // namespace blink
+
+#endif  // CSSPropertyWebkitBorderWidthUtils_h