YCM works correctly when 'out' directory is a symlink (continued).

tools/vim/chromium.ycm_extra_conf.py

 # 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.
 
 # Autocompletion config for YouCompleteMe in Chromium.
 #
 # USAGE:
 #
 #   1. Install YCM [https://github.com/Valloric/YouCompleteMe]
 #          (Googlers should check out [go/ycm])
@@ skipping 148 matching lines @@
     else:
       if filename.startswith(blink_root):
         # If this is a Blink file, we can at least try to get a reasonable
         # approximation.
         filename = default_blink_file
       else:
         # If this is a standalone .h file with no source, the best we can do is
         # try to use the default flags.
         return chrome_flags
 
-  out_dir = GetNinjaOutputDirectory(chrome_root)
+  out_dir = os.path.realpath(GetNinjaOutputDirectory(chrome_root))
 
   # Ninja needs the path to the source file relative to the output build
   # directory.
-  rel_filename = os.path.relpath(os.path.realpath(filename),
-                                 os.path.realpath(out_dir))
+  rel_filename = os.path.relpath(os.path.realpath(filename), out_dir)
 
   # Ask ninja how it would build our source file.
   p = subprocess.Popen(['ninja', '-v', '-C', out_dir, '-t',
                         'commands', rel_filename + '^'],
                        stdout=subprocess.PIPE)
   stdout, stderr = p.communicate()
   if p.returncode:
     return chrome_flags
 
   # Ninja might execute several commands to build something. We want the last
@@ skipping 41 matching lines @@
   """
   chrome_root = FindChromeSrcFromFilename(filename)
   chrome_flags = GetClangCommandFromNinjaForFilename(chrome_root,
                                                      filename)
   final_flags = flags + chrome_flags
 
   return {
     'flags': final_flags,
     'do_cache': True
   }