[Android][Signin] Create feature flag for the MobileIdentityConsistency FRE

This cl creates a new feature flag to host changes for Mobile Identity
Consistency in the First Run Experience (aka FRE).

Bug: 1189585
Change-Id: I9852bcbcc4f440451a434ea03a145bbe6b2a2a66
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2778323
Commit-Queue: Tanmoy Mollik <[email protected]>
Reviewed-by: Mihai Sardarescu <[email protected]>
Reviewed-by: Alice Wang <[email protected]>
Cr-Commit-Position: refs/heads/master@{#868492}
diff --git a/chrome/browser/flag_descriptions.cc b/chrome/browser/flag_descriptions.cc
index f94cdbf..09336868 100644
--- a/chrome/browser/flag_descriptions.cc
+++ b/chrome/browser/flag_descriptions.cc
@@ -1490,6 +1490,12 @@
     "Enables stronger identity consistency on mobile with different UI "
     "variations";
 
+const char kMobileIdentityConsistencyFREName[] =
+    "Mobile identity consistency FRE";
+const char kMobileIdentityConsistencyFREDescription[] =
+    "Enables stronger identity consistency on mobile with different UIs for "
+    "the First Run Experience.";
+
 const char kMobilePwaInstallUseBottomSheetName[] =
     "Mobile PWA Installation bottom sheet";
 const char kMobilePwaInstallUseBottomSheetDescription[] =