Get rid of TextbookModule and TextbookDescriptor.

common/lib/xmodule/xmodule/course_module.py

 from fs.errors import ResourceNotFoundError
 import time
 import logging
+from lxml import etree
 
 from xmodule.util.decorators import lazyproperty
 from xmodule.graders import load_grading_policy
 from xmodule.modulestore import Location
 from xmodule.seq_module import SequenceDescriptor, SequenceModule
 from xmodule.timeparse import parse_time, stringify_time
-from xmodule.textbook_module import TextbookDescriptor
 
 log = logging.getLogger(__name__)
 
-
 class CourseDescriptor(SequenceDescriptor):
     module_class = SequenceModule
 
+    class Textbook:
+        def __init__(self, title, table_of_contents_url):
+            self.title = title
+            self.table_of_contents_url = table_of_contents_url
+
+        @classmethod
+        def from_xml_object(cls, xml_object):
+            return cls(xml_object.get('title'), xml_object.get('table_of_contents_url'))
+
+        @property
+        def table_of_contents(self):
+            raw_table_of_contents = open(self.table_of_contents_url, 'r') # TODO: This will need to come from S3
+            table_of_contents = etree.parse(raw_table_of_contents).getroot()
+            return table_of_contents
+
+
     def __init__(self, system, definition=None, **kwargs):
         super(CourseDescriptor, self).__init__(system, definition, **kwargs)
+        self.textbooks = self.definition['textbooks']
 
         msg = None
         if self.start is None:
@@ -29,6 +45,16 @@ class CourseDescriptor(SequenceDescriptor):
         self.enrollment_start = self._try_parse_time("enrollment_start")
         self.enrollment_end = self._try_parse_time("enrollment_end")
 
+    @classmethod
+    def definition_from_xml(cls, xml_object, system):
+        textbooks = []
+        for textbook in xml_object.findall("textbook"):
+            textbooks.append(cls.Textbook.from_xml_object(textbook))
+            xml_object.remove(textbook)
+        definition =  super(CourseDescriptor, cls).definition_from_xml(xml_object, system)
+        definition['textbooks'] = textbooks
+        return definition
+
     def has_started(self):
         return time.gmtime() > self.start
 
@@ -54,11 +80,6 @@ class CourseDescriptor(SequenceDescriptor):
 
         return grading_policy
 
-    @property
-    def textbooks(self):
-        return [child for child in self.get_children() if type(child) == TextbookDescriptor]
-
-
     @lazyproperty
     def grading_context(self):
         """

common/lib/xmodule/xmodule/textbook_module.py

-from xmodule.x_module import XModule
-from xmodule.xml_module import XmlDescriptor
-from lxml import etree
-
-class TextbookModule(XModule):
-    def __init__(self, system, location, definition, descriptor, instance_state=None,
-                 shared_state=None, **kwargs):
-        XModule.__init__(self, system, location, definition, descriptor,
-                         instance_state, shared_state, **kwargs)
-
-    def get_display_items(self):
-      return []
-
-    def displayable_items(self):
-      return []
-
-class TextbookDescriptor(XmlDescriptor):
-
-    module_class = TextbookModule
-
-    def __init__(self, system, definition=None, **kwargs):
-        super(TextbookDescriptor, self).__init__(system, definition, **kwargs)
-        self.title = self.metadata["title"]
-
-    @classmethod
-    def definition_from_xml(cls, xml_object, system):
-        return { 'children': [] }
-
-    @property
-    def table_of_contents(self):
-        raw_table_of_contents = open(self.metadata['table_of_contents_url'], 'r') # TODO: This will need to come from S3
-        table_of_contents = etree.parse(raw_table_of_contents).getroot()
-        return table_of_contents