Fix UMA metric "WinJumplist.DirectoryStatusJumpListIconsOld"

The base::IsDirectoryEmpty() method returns true when the directory
doesn't exist or the directory is empty. We need to use
base::DirectoryExists() together with base::IsDirectoryEmpty() to
differentiate these two situations.

BUG=40407, 179576

Review-Url: https://codereview.chromium.org/2806873002
Cr-Commit-Position: refs/heads/master@{#463297}
diff --git a/chrome/browser/win/jumplist_file_util.cc b/chrome/browser/win/jumplist_file_util.cc
index 87b5d86..3cbb0aab 100644
--- a/chrome/browser/win/jumplist_file_util.cc
+++ b/chrome/browser/win/jumplist_file_util.cc
@@ -115,7 +115,8 @@
     FolderDeleteResult delete_status = DeleteDirectory(path, max_file_deleted);
     UMA_HISTOGRAM_ENUMERATION("WinJumplist.DeleteStatusJumpListIconsOld",
                               delete_status, FolderDeleteResult::END);
-    dir_status = base::IsDirectoryEmpty(path) ? EMPTY : NON_EMPTY;
+    if (base::DirectoryExists(path))
+      dir_status = base::IsDirectoryEmpty(path) ? EMPTY : NON_EMPTY;
   }
 
   UMA_HISTOGRAM_ENUMERATION("WinJumplist.DirectoryStatusJumpListIconsOld",