Start using file_util symlink code, now that it's available.

base/file_util_posix.cc

 // 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.
 
 #include "base/file_util.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
@@ skipping 370 matching lines @@
                    symlink_path.value().c_str()) != -1;
 }
 
 bool ReadSymbolicLink(const FilePath& symlink_path,
                       FilePath* target_path) {
   DCHECK(!symlink_path.empty());
   DCHECK(target_path);
   char buf[PATH_MAX];
   ssize_t count = ::readlink(symlink_path.value().c_str(), buf, arraysize(buf));
 
-  if (count <= 0)
+  if (count <= 0) {
+    target_path->clear();
     return false;
+  }
 
   *target_path = FilePath(FilePath::StringType(buf, count));
-
   return true;
 }
 
 // Creates and opens a temporary file in |directory|, returning the
 // file descriptor. |path| is set to the temporary file path.
 // This function does NOT unlink() the file.
 int CreateAndOpenFdForTemporaryFile(FilePath directory, FilePath* path) {
   base::ThreadRestrictions::AssertIOAllowed();  // For call to mkstemp().
   *path = directory.Append(kTempFileName);
   const std::string& tmpdir_string = path->value();
@@ skipping 474 matching lines @@
   if (HANDLE_EINTR(close(infile)) < 0)
     result = false;
   if (HANDLE_EINTR(close(outfile)) < 0)
     result = false;
 
   return result;
 }
 #endif  // defined(OS_MACOSX)
 
 }  // namespace file_util