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

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

Index: third_party/WebKit/Source/core/css/properties/CSSPropertyAPIWebkitBorderWidth.cpp
diff --git a/third_party/WebKit/Source/core/css/properties/CSSPropertyAPIWebkitBorderWidth.cpp b/third_party/WebKit/Source/core/css/properties/CSSPropertyAPIWebkitBorderWidth.cpp
index 399f5f47ba9e9a56e8d0cf096862ad76a21ab2a9..8cffddd017d9f15622e468f3dfb0f7ccdb583507 100644
--- a/third_party/WebKit/Source/core/css/properties/CSSPropertyAPIWebkitBorderWidth.cpp
+++ b/third_party/WebKit/Source/core/css/properties/CSSPropertyAPIWebkitBorderWidth.cpp
@@ -4,4 +4,18 @@
 
 #include "core/css/properties/CSSPropertyAPIWebkitBorderWidth.h"
 
-namespace blink {}  // namespace blink
+#include "core/css/parser/CSSParserContext.h"
+#include "core/css/parser/CSSPropertyParserHelpers.h"
+#include "core/css/properties/CSSPropertyWebkitBorderWidthUtils.h"
+
+namespace blink {
+
+const CSSValue* CSSPropertyAPIWebkitBorderWidth::parseSingleValue(
+    CSSParserTokenRange& range,
+    const CSSParserContext& context,
+    CSSPropertyID) {
+  return CSSPropertyWebkitBorderWidthUtils::ConsumeBorderWidth(
+      range, context.Mode(), CSSPropertyParserHelpers::UnitlessQuirk::kForbid);
+}
+
+}  // namespace blink