Disable UsernameFirstFlow by default

Bug: 1067208
Change-Id: I7c731470111440b9f5ca1100819dff780e847172
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2139720Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Auto-Submit: Dominic Battré <battre@chromium.org>
Commit-Queue: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757129}

components/password_manager/core/common/password_manager_features.cc

@@ -76,7 +76,7 @@ const base::Feature kRecoverFromNeverSaveAndroid = {
 
 // Enables support of filling and saving on username first flow.
 const base::Feature kUsernameFirstFlow = {"UsernameFirstFlow",
-                                          base::FEATURE_ENABLED_BY_DEFAULT};
+                                          base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Field trial identifier for password generation requirements.
 const char kGenerationRequirementsFieldTrial[] =

testing/variations/fieldtrial_testing_config.json

@@ -6240,8 +6240,8 @@
             ],
             "experiments": [
                 {
-                    "name": "Enabled",
-                    "enable_features": [
+                    "name": "Default",
+                    "disable_features": [
                         "UsernameFirstFlow"
                     ]
                 }