Add EnableFilesystemInIncognito feature and flag.

EnableFilesystemInIncognito feature and flag are added to control
activation of in-memory filesystem api for incognito mode.

Bug: 93417
Change-Id: I7002ff23afd0d1ceacf29be3b01ce6f2cd09410c
Reviewed-on: https://chromium-review.googlesource.com/c/1472290
Reviewed-by: Elly Fong-Jones <[email protected]>
Reviewed-by: Marijn Kruisselbrink <[email protected]>
Commit-Queue: Ramin Halavati <[email protected]>
Cr-Commit-Position: refs/heads/master@{#632512}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index 2fb4cf6..933b6ff1 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -523,6 +523,10 @@
     "Enable support for specifying a target element using a css selector in "
     "the fragment identifier.";
 
+const char kEnableFilesystemInIncognitoName[] = "Filesystem API in Incognito";
+const char kEnableFilesystemInIncognitoDescription[] =
+    "Enable Filesystem API in incognito mode.";
+
 const char kEnableNoScriptPreviewsName[] = "NoScript previews";
 
 const char kEnableNoScriptPreviewsDescription[] =