Added parseShorthand method from the parser to CSSPropertyAPI.h.

third_party/WebKit/Source/build/scripts/templates/CSSPropertyDescriptor.cpp.tmpl

Index: third_party/WebKit/Source/build/scripts/templates/CSSPropertyDescriptor.cpp.tmpl
diff --git a/third_party/WebKit/Source/build/scripts/templates/CSSPropertyDescriptor.cpp.tmpl b/third_party/WebKit/Source/build/scripts/templates/CSSPropertyDescriptor.cpp.tmpl
index 457060f0e4c2e1601451339999db441ff99cb75c..93e8ecb7b3908c1bf36c0b2625faec380feb7dba 100644
--- a/third_party/WebKit/Source/build/scripts/templates/CSSPropertyDescriptor.cpp.tmpl
+++ b/third_party/WebKit/Source/build/scripts/templates/CSSPropertyDescriptor.cpp.tmpl
@@ -17,11 +17,11 @@ static CSSPropertyDescriptor cssPropertyDescriptors[] = {
     // An invalid CSSPropertyDescriptor. When functions are added to
     // CSSPropertyAPI, add a nullptr to represent their function pointers in the
     // struct initaliser.

[meade_UTC10, 2017/01/25 04:28:18]

I'm not sure I understand what this does, it's creating a 2D array of function
pointers or null?

-    { nullptr, false },
+    { nullptr, nullptr },
     // When functions are added to CSSPropertyAPI, also add them to the struct
     // initaliser below.
     {% for api_class in api_classes %}
-    { {{api_class.classname}}::parseSingleValue, true },
+    { {{api_class.classname}}::parseSingleValue, {{api_class.classname}}::parseShorthand },

[meade_UTC10, 2017/01/25 04:28:18]

And in this case it's defining the default implementation and the subclass
implementation for this particular value..?

[aazzam, 2017/01/25 04:35:19]

the array cssPropertyDescriptors stores an invalid descriptor as the first
element, and a descriptor for each property with an implementation as every
other element. So the invalid descriptor is just nullptr for all the function
pointers. For every other descriptor, it will have a function pointer for
parseSingleValue, parseShorthand, etc. for that property

This CL just changes these struct initialiser lists so that they don't have the
bool value (I removed temporaryCanReadValue from the CSSPropertyDescriptor
struct) and added a pointer for parseShorthand, since this function was added to
the descriptor.

does that clarify your questions? :)

[meade_UTC10, 2017/01/25 05:26:27]

Maybe? :) I think it's worth changing the comments and/or code to make this
clearer. A couple of comments on this...

1- It's possible to have too many comments (!) - I think there were too many
words about what to do if you add a function to the CSSPropertyAPI that I lost
the meaning of the code.

2- I'd discourage having the first (or last) entry in an array being a special
value (sounds like a trap for people unfamilar with the code who might try
iterating everything obliviously)... You could split it out into two variables:

// An invalid CSSPropertyDescriptor containing null placeholders for each 
// method that could possibly be supported by a descriptor. It should have the 
// same length as each entry in cssPropertyDescriptors.
static CSSPropertyDescriptor invalidDescriptor[] = {nullptr, nullptr};
static CSSPropertyDescriptor cssPropertyDescriptors[] = {
  { {{api_class.classname}}::parseSingleValue,
      {{api_class.classname}}::parseShorthand },
};


Also: feel free to address these comments in a followup CL.

     {% endfor %}
 };