grit: Add fallback_to_default_layout attribute to <output>

grit/node/io.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 '''The <output> and <file> elements.
 '''
 
 import os
 
@@ skipping 59 matching lines @@
   '''An <output> element.'''
 
   def MandatoryAttributes(self):
     return ['filename', 'type']
 
   def DefaultAttributes(self):
     return {
       'lang' : '', # empty lang indicates all languages
       'language_section' : 'neutral', # defines a language neutral section
       'context' : '',
+      'fallback_to_default_layout' : 'true',
     }
 
   def GetType(self):
     return self.attrs['type']
 
   def GetLanguage(self):
     '''Returns the language ID, default 'en'.'''
     return self.attrs['lang']
 
   def GetContext(self):
     return self.attrs['context']
 
   def GetFilename(self):
     return self.attrs['filename']
 
   def GetOutputFilename(self):
     path = None
     if hasattr(self, 'output_filename'):
       path = self.output_filename
     else:
       path = self.attrs['filename']
     return os.path.expandvars(path)
 
+  def GetFallbackToDefaultLayout(self):
+    return self.attrs['fallback_to_default_layout'].lower() == 'true'
+
   def _IsValidChild(self, child):
     return isinstance(child, EmitNode)
 
 class EmitNode(base.ContentNode):
   ''' An <emit> element.'''
 
   def DefaultAttributes(self):
     return { 'emit_type' : 'prepend'}
 
   def GetEmitType(self):
     '''Returns the emit_type for this node. Default is 'append'.'''
     return self.attrs['emit_type']