When diffing against an old revision, handle the case if a file didn't exists.

scm.py

 # Copyright (c) 2010 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.
 
 """SCM-specific utility classes."""
 
 import cStringIO
 import glob
 import logging
 import os
@@ skipping 715 matching lines @@
         if info.get("Node Kind") != "directory":
           # svn diff on a mv/cp'd file outputs nothing if there was no change.
           data = SVN.Capture(command)
           if not data:
             # We put in an empty Index entry so upload.py knows about them.
             data = "Index: %s\n" % filename.replace(os.sep, '/')
         # Otherwise silently ignore directories.
     else:
       if info.get("Node Kind") != "directory":
         # Normal simple case.
-        data = SVN.Capture(command)
+        try:
+          data = SVN.Capture(command)
+        except gclient_utils.CheckCallError, e:
+          if revision:
+            data = GenFakeDiff(filename)
+          else:
+            raise
       # Otherwise silently ignore directories.
     return data
 
   @staticmethod
   def GenerateDiff(filenames, root=None, full_move=False, revision=None):
     """Returns a string containing the diff for the given file list.
 
     The files in the list should either be absolute paths or relative to the
     given root. If no root directory is provided, the repository root will be
     used.
@@ skipping 224 matching lines @@
       if (file_status[0][0] in ('D', 'A', '!') or
           not file_status[0][1:].isspace()):
         # Added, deleted file requires manual intervention and require calling
         # revert, like for properties.
         try:
           SVN.Capture(['revert', file_status[1]], cwd=repo_root)
         except gclient_utils.CheckCallError:
           if not os.path.exists(file_path):
             continue
           raise