Fix PRESUBMIT.py's path handling.

PRESUBMIT.py

 #!/usr/bin/python
 # Copyright (c) 2009 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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
 details on the presubmit API built into gcl.
 """
@@ skipping 69 matching lines @@
     found = False
     for item in excluded_paths:
       if item.match(path):
         found = True
         break
     if found:
       continue
 
     # Need to read the file ourselves since AffectedFile.NewContents()
     # will normalize line endings.
-    contents = ReadFile(path)
+    contents = ReadFile(f.AbsoluteLocalPath())
     if '\r' in contents:
       cr_files.append(path)
 
     # Check that the file ends in one and only one newline character.
     if len(contents) > 0 and (contents[-1:] != "\n" or contents[-2:-1] == "\n"):
       eof_files.append(path)
 
     local_errors = []
     # Remove end of line character.
     lines = contents.splitlines()
@@ skipping 27 matching lines @@
 
   if cr_files:
     results.append(output_api.PresubmitError(
         'Found CR (or CRLF) line ending in these files, please use only LF:',
         items=cr_files))
   if eof_files:
     results.append(output_api.PresubmitError(
         'These files should end in one (and only one) newline character:',
         items=eof_files))
   return results