[Passwords] Add flags enabling Saving UI for account-stored passwords

The new feature controls the saving UI only so that we can:
a) experiment with filling and saving independently
b) guard highly experimental and testing-only saving surfaces initially

Bug: 1018700
Change-Id: I44f190dac515a42cdf2173b89e9fded3ba4b3983
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1926129
Reviewed-by: Vasilii Sukhanov <[email protected]>
Commit-Queue: Friedrich [CET] <[email protected]>
Cr-Commit-Position: refs/heads/master@{#716985}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index b07b751..36923b2 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -4632,6 +4632,13 @@
      FEATURE_VALUE_TYPE(
          password_manager::features::kEnablePasswordsAccountStorage)},
 
+    {"passwords-account-storage-saving-ui",
+     flag_descriptions::kEnablePasswordsAccountStorageSavingUiName,
+     flag_descriptions::kEnablePasswordsAccountStorageSavingUiDescription,
+     kOsWin | kOsMac | kOsLinux,
+     FEATURE_VALUE_TYPE(
+         password_manager::features::kEnablePasswordsAccountStorageSavingUi)},
+
 #if !defined(OS_ANDROID)
     {"improved-cookie-controls", flag_descriptions::kImprovedCookieControlsName,
      flag_descriptions::kImprovedCookieControlsDescription, kOsDesktop,