[iOS] Add flag for Mobile Identity Consistency experiment.

Bug: 1125631
Change-Id: I643970c9131c34727d896f1fbabaa497003a37fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2396299Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Nohemi Fernandez <fernandex@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805255}

chrome/browser/flag-metadata.json

@@ -3102,7 +3102,7 @@
   },
   {
     "name": "mobile-identity-consistency",
-    "owners": [ "bsazonov", "aliceywang", "msarda" ],
+    "owners": [ "bsazonov", "aliceywang", "msarda", "fernandex" ],
     "expiry_milestone": 90
   },
   {

components/signin/public/base/account_consistency_method.cc

@@ -12,4 +12,9 @@ const base::Feature kMobileIdentityConsistency{
     "MobileIdentityConsistency", base::FEATURE_DISABLED_BY_DEFAULT};
 #endif
 
+#if defined(OS_IOS)
+const base::Feature kMobileIdentityConsistency{
+    "MobileIdentityConsistency", base::FEATURE_DISABLED_BY_DEFAULT};
+#endif
+
 }  // namespace signin

components/signin/public/base/account_consistency_method.h

@@ -14,7 +14,7 @@
 
 namespace signin {
 
-#if defined(OS_ANDROID)
+#if defined(OS_ANDROID) || defined(OS_IOS)
 // Mice is similar to Mirror but also works when the user is not opted into
 // Sync.
 extern const base::Feature kMobileIdentityConsistency;

ios/chrome/browser/flags/about_flags.mm

@@ -47,6 +47,7 @@
 #include "components/send_tab_to_self/features.h"
 #include "components/signin/core/browser/account_reconcilor.h"
 #include "components/signin/ios/browser/features.h"
+#include "components/signin/public/base/account_consistency_method.h"
 #include "components/signin/public/base/signin_switches.h"
 #include "components/strings/grit/components_strings.h"
 #include "components/sync/base/sync_base_switches.h"
@@ -687,6 +688,10 @@ const flags_ui::FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kScreenTimeIntegrationName,
      flag_descriptions::kScreenTimeIntegrationDescription, flags_ui::kOsIos,
      FEATURE_VALUE_TYPE(kScreenTimeIntegration)},
+    {"mobile-identity-consistency",
+     flag_descriptions::kMobileIdentityConsistencyName,
+     flag_descriptions::kMobileIdentityConsistencyDescription, flags_ui::kOsIos,
+     FEATURE_VALUE_TYPE(signin::kMobileIdentityConsistency)},
 };
 
 bool SkipConditionalFeatureEntry(const flags_ui::FeatureEntry& entry) {

ios/chrome/browser/flags/ios_chrome_flag_descriptions.cc

@@ -349,6 +349,10 @@ const char kMobileGoogleSRPDescription[] =
     "Request the Mobile version of Google SRP by default when the desktop mode "
     "is requested by default.";
 
+const char kMobileIdentityConsistencyName[] = "Mobile identity consistency";
+const char kMobileIdentityConsistencyDescription[] =
+    "Enables identity consistency on mobile by decoupling sync and sign-in.";
+
 const char kOmniboxPreserveDefaultMatchAgainstAsyncUpdateName[] =
     "Omnibox Preserve Default Match Against Async Update";
 const char kOmniboxPreserveDefaultMatchAgainstAsyncUpdateDescription[] =

ios/chrome/browser/flags/ios_chrome_flag_descriptions.h

@@ -302,6 +302,10 @@ extern const char kMarkHttpAsDescription[];
 extern const char kMobileGoogleSRPName[];
 extern const char kMobileGoogleSRPDescription[];
 
+// Title and description for the flag to enable mobile identity consistency.
+extern const char kMobileIdentityConsistencyName[];
+extern const char kMobileIdentityConsistencyDescription[];
+
 // Title and description for the flag to preserve the default match when an
 // async match updates.
 extern const char kOmniboxPreserveDefaultMatchAgainstAsyncUpdateName[];