Add depends attributes to Columns.

It allow to specify a list of fields that are needed in the view for this one.
Add active field by default in each views.

trytond/osv/fields.py

@@ -54,7 +54,7 @@ class Column(object):
             domain=None, context='', states=None, priority=0,
             change_default=False, size=None, ondelete="SET NULL",
             translate=False, select=0, on_change=None, on_change_with=None,
-            **args):
+            depends=None, **args):
         self.states = states or {}
         self.string = string
         self.readonly = readonly
@@ -67,6 +67,7 @@ class Column(object):
         self.translate = translate
         self._domain = domain or []
         self._context = context
+        self.depends = depends or []
         if select not in (0, 1, 2):
             raise Exception('Error', 'Select must be one of 0, 1, 2')
         self.select = select

trytond/osv/orm.py

@@ -2184,6 +2184,18 @@ class ORM(object):
 
         fields_def = self.__view_look_dom(cursor, user, tree_root, type,
                 fields_width=fields_width, context=context)
+
+        for field_name in fields_def.keys():
+            if field_name in self._columns:
+                field = self._columns[field_name]
+            else:
+                field = self._inherit_fields[field_name][2]
+            for depend in field.depends:
+                fields_def.setdefault(depend, {})
+
+        if ('active' in self._columns) or ('active' in self._inherit_fields):
+            fields_def.setdefault('active', {'select': "2"})
+
         arch = etree.tostring(tree, encoding='utf-8', pretty_print=False)
         fields2 = self.fields_get(cursor, user, fields_def.keys(), context)
         for field in fields_def: