Allow non-absolute path for variables. This fixes grit to do variable

tools/grit/grit/grd_reader_unittest.py

 #!/usr/bin/python2.4
 # Copyright (c) 2011 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.
 
 '''Unit tests for grd_reader package'''
 
 import os
 import sys
 if __name__ == '__main__':
@@ skipping 128 matching lines @@
         test2
       </message>
     </messages>
   </release>
 </grit>'''
     pseudo_file = StringIO.StringIO(input)
     root = grd_reader.Parse(pseudo_file, '.')
     grit_root_dir = os.path.join(os.path.abspath(os.path.dirname(__file__)),
                                  '..')
     root.AssignFirstIds(
-        # This file does not actually exist, but the path must match
-        # the path of the resource_ids file as it has SRCDIR set to "."
-        os.path.join(grit_root_dir, "grit/testdata/test.grd"),
+        # This file does not actually exist, but must use absolute
+        # path as resource_ids has '' for SRCDIR (see special handling
+        # in grit.node.misc).
+        os.path.join(grit_root_dir, "/test.grd"),
         os.path.join(grit_root_dir, "grit/testdata/resource_ids"),
         {})
     messages_node = root.children[0].children[0]
     self.assertTrue(isinstance(messages_node, empty.MessagesNode))
     self.assertEqual('100', messages_node.attrs["first_id"])
     messages_node = root.children[0].children[1]
     self.assertTrue(isinstance(messages_node, empty.MessagesNode))
     self.assertEqual('10000', messages_node.attrs["first_id"])
 
   def testUseNameForIdAndPpIfdef(self):
@@ skipping 12 matching lines @@
     pseudo_file = StringIO.StringIO(input)
     root = grd_reader.Parse(pseudo_file, '.', defines={'hello': '1'})
 
     # Check if the ID is set to the name. In the past, there was a bug
     # that caused the ID to be a generated number.
     hello = root.GetNodeById('IDS_HELLO')
     self.failUnless(hello.GetCliques()[0].GetId() == 'IDS_HELLO')
 
 if __name__ == '__main__':
   unittest.main()