Added CSSPropertyAPI and CSS padding properties which implement this API

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

+// Copyright 2016 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 CSSPropertyAPI_h
+#define CSSPropertyAPI_h
+
+#include "core/CSSPropertyNames.h"
+#include "core/css/CSSValue.h"
+#include "core/css/parser/CSSParserMode.h"
+#include "core/css/parser/CSSParserTokenRange.h"
+
+namespace blink {
+
+/*
+An API for CSS properties which allows you to call functions on properties
+from within the parser. To enusre that all functions are implemented, provide
+implementations for all functions with a default implementation or
+NOTREACHED().
+*/
+class CSSPropertyAPI {
+ public:
+  // Parses the CSS property and returns a CSS Value.
+  static const CSSValue* parseSingleValue(CSSParserTokenRange&,
+                                          const CSSParserContext&) {
+    NOTREACHED();
+    return nullptr;
+  }
+
+  // Returns the CSSPropertyID of the property
+  static inline CSSPropertyID getID() {
+    NOTREACHED();
+    return CSSPropertyInvalid;
+  }
+};
+}

[alancutter (OOO until 2018), 2016/11/29 06:51:49]

I don't think this class is necessary. Without it the "subclasses" will hit
compile errors for any methods they don't implement saving you the need to
DCHECK anything.

[aazzam, 2016/11/30 23:32:53]

I think we should keep the class since it's a way of seeing all the methods that
our API has. It's also needed in the future where we have methods which aren't
implemented by every property, and we'll want to have a default implementation.
I've changed the code now so that we don't need to use NOTREACHED() on our not
implemented functions.

+
+#endif  // CSSPropertyAPI_h