[Files Ranking] Add a chrome flag.

Bug: 959679
Test: unit_tests
Change-Id: I9d7c7ae889ae460cb01c280ef79be751a4563889
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1765033
Commit-Queue: Tony Yeoman <[email protected]>
Reviewed-by: Jia Meng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#689781}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 9f672ee9..ce3a0f44d 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -2126,6 +2126,9 @@
 extern const char kWakeOnPacketsName[];
 extern const char kWakeOnPacketsDescription[];
 
+extern const char kZeroStateFilesName[];
+extern const char kZeroStateFilesDescription[];
+
 // Prefer keeping this section sorted to adding new declarations down here.
 
 #endif  // #if defined(OS_CHROMEOS)