Add a switch for enabling the ManagePasswordsBubbleUI to the about:flags page.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index ff9d3e582c06e53a78ca42dab190360312f0701f..dc0f28c98aeff8790a676ef45de6237f5d3fee11 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1950,7 +1950,16 @@ const Experiment kExperiments[] = {
     IDS_FLAGS_ENABLE_IGNORE_AUTOCOMPLETE_OFF_DESCRIPTION,
     kOsAll,
     SINGLE_VALUE_TYPE(autofill::switches::kEnableIgnoreAutocompleteOff)
+  },
+  #if defined(USE_AURA) || defined(OS_WIN)
+  {
+    "enable-save-password-bubble",
+    IDS_FLAGS_ENABLE_SAVE_PASSWORD_BUBBLE_NAME,
+    IDS_FLAGS_ENABLE_SAVE_PASSWORD_BUBBLE_DESCRIPTION,
+    kOsWin | kOsLinux,
+    SINGLE_VALUE_TYPE(switches::kEnableSavePasswordBubble)
   }
+  #endif
 };
 
 const Experiment* experiments = kExperiments;