[xlang] Cross language Python support (#6709)

python/ray/includes/common.pxd

@@ -13,6 +13,9 @@ from ray.includes.unique_ids cimport (
     CObjectID,
     CTaskID,
 )
+from ray.includes.function_descriptor cimport (
+    CFunctionDescriptor,
+)
 
 
 cdef extern from * namespace "polyfill":
@@ -201,9 +204,9 @@ cdef extern from "ray/core_worker/common.h" nogil:
     cdef cppclass CRayFunction "ray::RayFunction":
         CRayFunction()
         CRayFunction(CLanguage language,
-                     const c_vector[c_string] function_descriptor)
+                     const CFunctionDescriptor &function_descriptor)
         CLanguage GetLanguage()
-        const c_vector[c_string]& GetFunctionDescriptor()
+        const CFunctionDescriptor GetFunctionDescriptor()
 
     cdef cppclass CTaskArg "ray::TaskArg":
         @staticmethod