Added CSSPropertyAPI.h.tmpl to generate CSSPropertyAPI.h.

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 "wtf/Allocator.h"
-
-namespace blink {
-
-class CSSValue;
-class CSSParserContext;
-class CSSParserTokenRange;
-
-// We will use this API to represent all functions used for property-specific
-// logic inside the blink style engine. All specific properties are subclasses
-// of CSSPropertyAPI.
-//
-// To add a new implementation of this API for a property:
-// - Make a class that implements CSSPropertyAPI.
-// - For each method that you wish to implement in this class, add this method
-//   name to the api_methods flag in CSSProperties.json5.
-// - Implement these methods in the .cpp file.
-//
-// To add new functions to this API:
-// - Add the function to the struct below.
-// - Add the function name to the valid_values field for api_methods in
-//   CSSProperties.json5.
-class CSSPropertyAPI {
-  STATIC_ONLY(CSSPropertyAPI);
-
- public:
-  // Parses a single CSS property and returns the corresponding CSSValue. If the
-  // input is invalid it returns nullptr.
-  static const CSSValue* parseSingleValue(CSSParserTokenRange&,
-                                          const CSSParserContext*) {
-    // No code should reach here, since properties either have their own
-    // implementations of this method or store nullptr in their descriptor.
-    NOTREACHED();
-    return nullptr;
-  }
-
-  static bool parseShorthand(bool,
-                             CSSParserTokenRange&,
-                             const CSSParserContext*) {
-    // No code should reach here, since properties either have their own
-    // implementations of this method or store nullptr in their descriptor.
-    NOTREACHED();
-    return false;
-  }
-};
-
-}  // namespace blink
-
-#endif  // CSSPropertyAPI_h