Made a generator for CSSPropertyDescriptor.cpp

third_party/WebKit/Source/core/css/CSSProperties.in

 // This file specifies all the CSS properties we support and the necessary
 // information for our code generation. The various supported arguments
 // are described below with example usage
 
 
 // - alias_for=other-property
 // Properties specifying alias_for should be virtually identical to the
 // properties they alias. Minor parsing differences are allowed as long as
 // the CSSValues created are of the same format of the aliased property.
 
 
 // - runtime_flag=CSSGridLayout
 // The flag on RuntimeEnabledFeatures conditionally enables the property.
 // This doesn't currently work with alias_for.
 
 
 // - descriptor_only
 // These are actually descriptors and not CSS properties. Properties with
 // the same name as a descriptor do not get this flag.
 
 
 // - longhands=property;other-property
 // The property is a shorthand for several other properties.
 
 
+// - generated_api_class[=group]
+// We have a CSSPropertyAPI interface which contains parsing functions for
+// properties, and will be implemented by all CSS properties.
+// * When we want to generate the .h file for a property, we add this flag.

[sashab, 2016/12/08 23:56:35]

Small nit: instead of saying "we", phrase stuff like following a recipe, e.g.

* To add a property to the API, add this flag to the property

Also we're not generating the .h files in this patch anymore :)

[aazzam, 2016/12/09 00:44:39]

tried re-wording, ptal :)

+// * Properties which have the same parsing logic should be grouped together when
+//   generating an API .h file for the property. If the specified property is in
+//   a group, the  value of that flag should be set to the group name - all of

[sashab, 2016/12/08 23:56:35]

Remove double space before value

Also explain that the name here has to be the name of the file containing the
API class, as well as the name of that class

The comment doesn't have to be long, it just has to be thorough :)

+//   the properties with this flag value will inherit from a class with this name.
+// * Properties which are not generated do not get this flag.
+// TODO(aazzam): Once all .h files are generated, change this so that only grouped
+// properties have this flag and introduce a 'not_generated' flag instead.
+
+
 // - keyword_only
 // These properties only store keyword values. This is used when
 // generating the ComputedStyle storage for the property. The initial
 // value for this property on a ComputedStyle is specified with the
 // initial_keyword flag below.
 // TODO(sashab, meade): Remove this once TypedOM types are specified for
 // every property, since this value can be inferred from that.
 
 
 // - keywords=[keyword1|keyword2]
@@ skipping 425 matching lines @@
 -webkit-border-before-color direction_aware
 -webkit-border-before-style direction_aware
 -webkit-border-before-width direction_aware
 -webkit-border-after-color direction_aware
 -webkit-border-after-style direction_aware
 -webkit-border-after-width direction_aware
 -webkit-margin-end direction_aware
 -webkit-margin-start direction_aware
 -webkit-margin-before direction_aware
 -webkit-margin-after direction_aware
--webkit-padding-end direction_aware
--webkit-padding-start direction_aware
--webkit-padding-before direction_aware
--webkit-padding-after direction_aware
+-webkit-padding-end direction_aware, generated_api_class=WebkitPadding
+-webkit-padding-start direction_aware, generated_api_class=WebkitPadding
+-webkit-padding-before direction_aware, generated_api_class=WebkitPadding
+-webkit-padding-after direction_aware, generated_api_class=WebkitPadding
 -webkit-logical-width direction_aware
 -webkit-logical-height direction_aware
 -webkit-min-logical-width direction_aware
 -webkit-min-logical-height direction_aware
 -webkit-max-logical-width direction_aware
 -webkit-max-logical-height direction_aware
 
 // Properties that we ignore in the StyleBuilder.
 // TODO(timloh): This seems wrong, most of these shouldn't reach the StyleBuilder
 
@@ skipping 132 matching lines @@
 -webkit-text-size-adjust alias_for=text-size-adjust
 -webkit-transform alias_for=transform
 -webkit-transform-origin alias_for=transform-origin
 -webkit-transform-style alias_for=transform-style
 -webkit-transition alias_for=transition
 -webkit-transition-delay alias_for=transition-delay
 -webkit-transition-duration alias_for=transition-duration
 -webkit-transition-property alias_for=transition-property
 -webkit-transition-timing-function alias_for=transition-timing-function
 -webkit-user-select alias_for=user-select