Fix the new First Run sentinel file path determination.

chrome/installer/util/install_util.h

Index: chrome/installer/util/install_util.h
diff --git a/chrome/installer/util/install_util.h b/chrome/installer/util/install_util.h
index 5bc6b912afeb04a939a95cd5953f33273c0f06ab..53d389f4b672c9981a6547a06aa9d6492b987e07 100644
--- a/chrome/installer/util/install_util.h
+++ b/chrome/installer/util/install_util.h
@@ -106,6 +106,9 @@ class InstallUtil {
   // by either --chrome-sxs or the executable path).
   static bool IsChromeSxSProcess();
 
+  // Returns true if the sentinel file exists (or the path cannot be obtained).
+  static bool IsFirstRunSentinelPresent();
+
   // Populates |path| with the path to |file| in the sentinel directory for
   // |dist|. Returns false on error.
   static bool GetSentinelFilePath(const base::FilePath::CharType* file,