Implements CSSPropertyAPI for the clip-path property.

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIClipPath.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/CSSPropertyAPIClipPath.h"
+
+#include "core/css/CSSURIValue.h"
+#include "core/css/parser/CSSPropertyParserHelpers.h"
+#include "core/css/properties/CSSPropertyShapeUtils.h"
+
+namespace blink {
+
+using namespace CSSPropertyParserHelpers;

[aazzam, 2017/01/20 03:15:56]

I'm not sure if our style conventions prefer using "using namespace", or just
referring to the functions as CSSPropertyParserHelpers::...()
Added sasha to check :)

[ktyliu, 2017/01/20 03:18:41]

I am happy either way.
Fwiw, I originally didn't have the "using ..." but found that I need it in two
places -- consumeUrl and consumeIdent. Having it in consumeUrl (within if and
assignment) doesn't look terribly pretty so I went with "using ..."

[sashab, 2017/01/20 03:46:48]

Huh, I totally forgot about 'using namespace'... Umm we haven't used it in any
of the other API files, so for consistency let's leave it out. I don't think we
use it much in blink anyway (codesearch found 5k results but they are mainly
actual namespaces like v8, std, etc -
https://cs.chromium.org/search/?q=%22using+namespace%22&sq=package:chromium&t...)
and at some point I think we're gonna change CSSPropertyParserHelpers to not be
a namespace, so its more futureproof without it. :^)

[ktyliu, 2017/01/20 03:53:59]

Done.

Sounds good to be consistent :)

+
+const CSSValue* CSSPropertyAPIClipPath::parseSingleValue(
+    CSSParserTokenRange& range,
+    const CSSParserContext* context) {
+  if (range.peek().id() == CSSValueNone)
+    return consumeIdent(range);
+  if (CSSURIValue* url = consumeUrl(range, context))
+    return url;
+  return CSSPropertyShapeUtils::consumeBasicShape(range, context);
+}
+
+}  // namespace blink