Remove some deprecated file_util wstring functions.

chrome/installer/setup/setup_main.cc

Index: chrome/installer/setup/setup_main.cc
===================================================================
--- chrome/installer/setup/setup_main.cc	(revision 29006)
+++ chrome/installer/setup/setup_main.cc	(working copy)
@@ -67,7 +67,7 @@
   // Check if this is differential update and if it is, patch it to the
   // installer archive that should already be on the machine. We assume
   // it is a differential installer if chrome.7z is not found.
-  if (!file_util::PathExists(uncompressed_archive)) {
+  if (!file_util::PathExists(FilePath::FromWStringHack(uncompressed_archive))) {
     incremental_install = true;
     LOG(INFO) << "Differential patch found. Applying to existing archive.";
     if (!installed_version) {
@@ -163,10 +163,11 @@
   // either does not exist or can be deleted (i.e. is not locked by some other
   // process).
   if (!installed_version) {
-    std::wstring install_path(installer::GetChromeInstallPath(system_install));
+    FilePath install_path = FilePath::FromWStringHack(
+        installer::GetChromeInstallPath(system_install));
     if (file_util::PathExists(install_path) &&
         !file_util::Delete(install_path, true)) {
-      LOG(ERROR) << "Installation directory " << install_path
+      LOG(ERROR) << "Installation directory " << install_path.value()
                  << " exists and can not be deleted.";
       status = installer_util::INSTALL_DIR_IN_USE;
       int str_id = IDS_INSTALL_DIR_IN_USE_BASE;