Fix duplicate WebUI WallpaperHandler registration in OSSettingsUI

It was accidentally being registered twice. This didn't cause any
user-visible issues, but made the code confusing.

Bug: none
Test: wallpaper picker still opens from OS settings
Change-Id: Ica83d04267ae16d79e4f379e03ea7b6e47110fdf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2062796
Commit-Queue: James Cook <jamescook@chromium.org>
Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Auto-Submit: James Cook <jamescook@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742249}

chrome/browser/ui/webui/settings/chromeos/os_settings_ui.cc

@@ -162,8 +162,6 @@ OSSettingsUI::OSSettingsUI(content::WebUI* web_ui)
       std::make_unique<::settings::ProtocolHandlersHandler>());
   AddSettingsPageUIHandler(
       std::make_unique<::settings::SearchEnginesHandler>(profile));
-  AddSettingsPageUIHandler(
-      std::make_unique<chromeos::settings::WallpaperHandler>(web_ui));
 
   html_source->AddBoolean("showAppManagement", base::FeatureList::IsEnabled(
                                                    ::features::kAppManagement));
@@ -302,8 +300,6 @@ void OSSettingsUI::InitOSWebUIHandlers(content::WebUIDataSource* html_source) {
   web_ui()->AddMessageHandler(
       std::make_unique<chromeos::settings::KeyboardHandler>());
 
-  // TODO(crbug/950007): Remove adding WallpaperHandler when
-  // SplitSettings complete.
   web_ui()->AddMessageHandler(
       std::make_unique<chromeos::settings::WallpaperHandler>(web_ui()));