Fix the YCM tests on Mac.

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 62 matching lines @@
 
   Simply checks parent directories until it finds .gclient and src/.
 
   Args:
     filename: (String) Path to source file being edited.
 
   Returns:
     (String) Path of 'src/', or None if unable to find.
   """
   curdir = os.path.normpath(os.path.dirname(filename))
-  while not (os.path.basename(os.path.realpath(curdir)) == 'src'
+  while not (os.path.basename(curdir) == 'src'
              and PathExists(curdir, 'DEPS')
              and (PathExists(curdir, '..', '.gclient')
                   or PathExists(curdir, '.git'))):
     nextdir = os.path.normpath(os.path.join(curdir, '..'))
     if nextdir == curdir:
       return None
     curdir = nextdir
   return curdir
 
 
@@ skipping 58 matching lines @@
   Args:
     out_dir: (String) Absolute path to ninja build output directory.
     filename: (String) Absolute path to source file.
 
   Returns:
     (List of Strings) List of target names. Will return [] if |filename| doesn't
         yield any .o or .obj outputs.
   """
   # Ninja needs the path to the source file relative to the output build
   # directory.
-  rel_filename = os.path.relpath(os.path.realpath(filename), out_dir)
+  rel_filename = os.path.relpath(filename, out_dir)
 
   p = subprocess.Popen(['ninja', '-C', out_dir, '-t', 'query', rel_filename],
                        stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
                        universal_newlines=True)
   stdout, _ = p.communicate()
   if p.returncode != 0:
     return []
 
   # The output looks like:
   #   ../../relative/path/to/source.cc:
@@ skipping 140 matching lines @@
   additional_flags = ['-I' + os.path.join(chrome_root)]
 
   # Version of Clang used to compile Chromium can be newer then version of
   # libclang that YCM uses for completion. So it's possible that YCM's libclang
   # doesn't know about some used warning options, which causes compilation
   # warnings (and errors, because of '-Werror');
   additional_flags.append('-Wno-unknown-warning-option')
 
   sys.path.append(os.path.join(chrome_root, 'tools', 'vim'))
   from ninja_output import GetNinjaOutputDirectory
-  out_dir = os.path.realpath(GetNinjaOutputDirectory(chrome_root))
+  out_dir = GetNinjaOutputDirectory(chrome_root)
 
   clang_line = GetClangCommandLineFromNinjaForSource(
       out_dir, GetBuildableSourceFile(chrome_root, filename))
   if not clang_line:
     # If ninja didn't know about filename or it's companion files, then try a
     # default build target. It is possible that the file is new, or build.ninja
     # is stale.
     clang_line = GetClangCommandLineFromNinjaForSource(
         out_dir, GetDefaultSourceFile(chrome_root, filename))
 
@@ skipping 22 matching lines @@
   # transient failure. Preventing YCM from caching the flags allows us to try to
   # determine the flags again.
   should_cache_flags_for_file = bool(clang_flags)
 
   final_flags = _default_flags + clang_flags
 
   return {
     'flags': final_flags,
     'do_cache': should_cache_flags_for_file
   }