GRIT: Enable variable expansion in filenames during HTML inlining.

grit/gather/interface.py

Index: grit/gather/interface.py
diff --git a/grit/gather/interface.py b/grit/gather/interface.py
index 084392ad280ce5f83a9b4db5de81e59570baa00a..c277d379b3cc98b87049ff1fe07fe9d4c88e2332 100644
--- a/grit/gather/interface.py
+++ b/grit/gather/interface.py
@@ -152,6 +152,10 @@ class GathererBase(object):
     '''
     pass
 
+  def SetFilenameExpansionFunction(self, fn):
+    '''Sets a function for rewriting filenames before gathering.'''
+    pass
+
   # TODO(benrg): Move this elsewhere, since it isn't part of the interface.
   def _LoadInputFile(self):
     '''A convenience function for subclasses that loads the contents of the