Updated stale generated class comment in CSSPropertyAPI.h

third_party/WebKit/Source/build/scripts/templates/CSSPropertyAPI.h.tmpl

 // 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 "platform/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.
+// Base class for property APIs that contain logic for handling individual
+// properties.
+// The methods declared here are standard methods among property APIs, and can
+// be called on a particular property API through a CSSPropertyDescriptor
+// object.
+// Note that not all methods are implemented by all property APIs. Methods that
+// are not implemented on a property API will return nullptr when accessed
+// through a CSSPropertyDescriptor.
+// See the api_methods field on properties defined in CSSProperties.json5 for a
+// definition of which methods are implemented on a property.
 //
-// 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.
+// Status (5th May 2017): Eventually, all property specific logic will be
+// contained within property APIs that inherit from CSSPropertyAPI.
+// Currently, the code base is in a transitional state and property specific
+// logic is still scattered around the code base.
 class CSSPropertyAPI {
   STATIC_ONLY(CSSPropertyAPI);
 
  public:
   {% for api_method_name in ordered_api_method_names %}
   {% set api_method = all_api_methods[api_method_name] %}
   {% if api_method.description %}
   // {{api_method.description}}
   {% endif %}
   static {{api_method.return_type}} {{api_method_name}}{{api_method.parameters}};
   {% endfor %}
 };
 
 } // namespace blink
 
 #endif // CSSPropertyAPI_h