[PasswordManager] Stop Using Native Backends on Linux systems

Recent migrations moved all users who have been using the keying to the
LoginDatabase. This CL forces all users to using LoginDatabase
instead of native backends on Linux.

TBR=pcc@chromium.org

Change-Id: Ibac11e68d8f354ecf7f3c9828d95777ea5b3df60
Bug: 950269, 950267
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1713560
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Reviewed-by: Peter Collingbourne <pcc@chromium.org>
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Commit-Queue: Mohamed Amir Yosef <mamir@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681042}

chrome/browser/BUILD.gn

@@ -3850,8 +3850,6 @@ jumbo_split_static_library("browser") {
       "first_run/upgrade_util_linux.cc",
       "first_run/upgrade_util_linux.h",
       "icon_loader_auralinux.cc",
-      "password_manager/native_backend_kwallet_x.cc",
-      "password_manager/native_backend_kwallet_x.h",
       "platform_util_linux.cc",
       "shell_integration_linux.cc",
       "shell_integration_linux.h",
@@ -3883,16 +3881,6 @@ jumbo_split_static_library("browser") {
       ]
     }
 
-    # libsecret hard depends on GLib.
-    if (use_glib) {
-      sources += [
-        "password_manager/native_backend_libsecret.cc",
-        "password_manager/native_backend_libsecret.h",
-      ]
-      defines += [ "USE_LIBSECRET" ]
-      deps += [ "//third_party/libsecret" ]
-    }
-
     if (use_ozone) {
       sources += [
         "fullscreen_ozone.cc",
@@ -5083,14 +5071,6 @@ jumbo_split_static_library("browser") {
     configs += [ "//printing:cups" ]
   }
 
-  if (use_gnome_keyring) {
-    sources += [
-      "password_manager/native_backend_gnome_x.cc",
-      "password_manager/native_backend_gnome_x.h",
-    ]
-    configs += [ "//components/os_crypt:gnome_keyring" ]
-  }
-
   if (use_nss_certs) {
     sources += [
       "certificate_manager_model.cc",