Use the new product.default_uom.category keyword to search on uom

invoice.py

@@ -1259,7 +1259,8 @@ class InvoiceLine(OSV):
             states={
                 'required': "product",
                 'invisible': "type != 'line'",
-            }, domain="[('category', '=', (product, 'product'))]")
+            }, domain="[('category', '=', " \
+                    "(product, 'product.default_uom.category'))]")
     unit_digits = fields.Function('get_unit_digits', type='integer',
             string='Unit Digits', on_change_with=['unit'])
     product = fields.Many2One('product.product', 'Product',
@@ -1995,39 +1996,6 @@ class Template(OSV):
 Template()
 
 
-class Uom(OSV):
-    _name = 'product.uom'
-
-    def search(self, cursor, user, args, offset=0, limit=None, order=None,
-            context=None, count=False, query_string=False):
-        product_obj = self.pool.get('product.product')
-        args = args[:]
-        def process_args(args):
-            i = 0
-            while i < len(args):
-                if isinstance(args[i], list):
-                    process_args(args[i])
-                if isinstance(args[i], tuple) \
-                        and args[i][0] == 'category' \
-                        and isinstance(args[i][2], (list, tuple)) \
-                        and len(args[i][2]) == 2 \
-                        and args[i][2][1] == 'product':
-                    if not args[i][2][0]:
-                        args[i] = ('id', '!=', '0')
-                    else:
-                        product = product_obj.browse(cursor, user,
-                                args[i][2][0], context=context)
-                        category_id = product.default_uom.category.id
-                        args[i] = (args[i][0], args[i][1], category_id)
-                i += 1
-        process_args(args)
-        return super(Uom, self).search(cursor, user, args, offset=offset,
-                limit=limit, order=order, context=context, count=count,
-                query_string=query_string)
-
-Uom()
-
-
 class FiscalYear(OSV):
     _name = 'account.fiscalyear'
     out_invoice_sequence = fields.Many2One('ir.sequence.strict',