Introduce Diagnostics app feature flag

Bug: 1120206
Change-Id: I33cf4b17eac6f527877d82fcf31e8b39770d0ef2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2368102
Commit-Queue: Jimmy Gong <[email protected]>
Reviewed-by: Bailey Berro <[email protected]>
Cr-Commit-Position: refs/heads/master@{#801212}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 3a104148..81ad470 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -489,6 +489,9 @@
 extern const char kCrossOriginIsolatedName[];
 extern const char kCrossOriginIsolatedDescription[];
 
+extern const char kDiagnosticsAppName[];
+extern const char kDiagnosticsAppDescription[];
+
 extern const char kDisableKeepaliveFetchName[];
 extern const char kDisableKeepaliveFetchDescription[];