Support WebIDL optional default value syntax

Source/bindings/scripts/v8_methods.py

Index: Source/bindings/scripts/v8_methods.py
diff --git a/Source/bindings/scripts/v8_methods.py b/Source/bindings/scripts/v8_methods.py
index 4cb00489c1f47da8882505ab320504f675e3ce1c..533e903f68821aa1f593e9313bdac1fed3fd2ea3 100644
--- a/Source/bindings/scripts/v8_methods.py
+++ b/Source/bindings/scripts/v8_methods.py
@@ -168,6 +168,7 @@ def generate_argument(interface, method, argument, index):
         'vector_type': v8_types.cpp_ptr_type('Vector', 'HeapVector', idl_type.gc_type),
         'is_wrapper_type': idl_type.is_wrapper_type,
         'name': argument.name,
+        'default_value': argument.default_value,

[Nils Barth (inactive), 2014/05/16 12:22:54]

Alphabetical order please.

         'v8_set_return_value_for_main_world': v8_set_return_value(interface.name, method, this_cpp_value, for_main_world=True),
         'v8_set_return_value': v8_set_return_value(interface.name, method, this_cpp_value),
         'v8_value_to_local_cpp_value': v8_value_to_local_cpp_value(argument, index),
@@ -195,7 +196,8 @@ def cpp_value(interface, method, number_of_arguments):
         return argument.name
 
     # Truncate omitted optional arguments

[Nils Barth (inactive), 2014/05/16 12:22:54]

Could you move these down to the cpp_arguments.extend() lines, and omit the
auxiliary variables?
(We tend to avoid these if possible.)

-    arguments = method.arguments[:number_of_arguments]
+    required_arguments = method.arguments[:number_of_arguments]
+    optional_arguments = method.arguments[number_of_arguments:]
     cpp_arguments = v8_utilities.call_with_arguments(method)
     # Members of IDL partial interface definitions are implemented in C++ as
     # static member functions, which for instance members (non-static members)
@@ -203,7 +205,8 @@ def cpp_value(interface, method, number_of_arguments):
     if ('PartialInterfaceImplementedAs' in method.extended_attributes and
         not method.is_static):
         cpp_arguments.append('*impl')
-    cpp_arguments.extend(cpp_argument(argument) for argument in arguments)
+    cpp_arguments.extend(cpp_argument(argument) for argument in required_arguments)

[Nils Barth (inactive), 2014/05/16 12:22:54]

Line breaks please, here and next line:
loop and condition both on separate lines.

+    cpp_arguments.extend(argument.default_value for argument in optional_arguments if argument.is_optional and argument.default_value)
     this_union_arguments = method.idl_type and method.idl_type.union_arguments
     if this_union_arguments:
         cpp_arguments.extend(this_union_arguments)