Allow master view to decide whether each grid checkbox is checked

aka. un-break what the v3 grids broke..

tailbone/grids/core.py

@@ -56,7 +56,7 @@ class Grid(object):
                  joiners={}, filterable=False, filters={},
                  sortable=False, sorters={}, default_sortkey=None, default_sortdir='asc',
                  pageable=False, default_pagesize=20, default_page=1,
-                 checkboxes=False, main_actions=[], more_actions=[],
+                 checkboxes=False, checked=None, main_actions=[], more_actions=[],
                  **kwargs):
 
         self.key = key
@@ -90,6 +90,9 @@ class Grid(object):
         self.default_page = default_page
 
         self.checkboxes = checkboxes
+        self.checked = checked
+        if self.checked is None:
+            self.checked = lambda item: False
         self.main_actions = main_actions
         self.more_actions = more_actions
 
@@ -882,13 +885,6 @@ class Grid(object):
         """
         return True
 
-    def checked(self, item):
-        """
-        Returns boolean indicating whether the given item's row checkbox should
-        be checked, for initial page load.
-        """
-        return False
-
     def render_checkbox(self, item):
         """
         Renders a checkbox cell for the given item, if applicable.

tailbone/views/master2.py

@@ -258,6 +258,7 @@ class MasterView2(MasterView):
             'url': lambda obj: self.get_action_url('view', obj),
             'checkboxes': self.checkboxes or (
                 self.mergeable and self.request.has_perm('{}.merge'.format(self.get_permission_prefix()))),
+            'checked': self.checked,
         }
         if 'main_actions' not in kwargs and 'more_actions' not in kwargs:
             main, more = self.get_grid_actions()