dark_mode: Set background of DeskNameView inside OnThemeChanged.

This is a revert of the changes of DeskNameView at crrev.com/c/2486781.
Since Textfield::OnThemeChanged SetBackground, we should override it
at DeskNameView::OnThemeChanged to have our own background.

Bug: 1142692
Change-Id: I24b78bd730b010a60180782d646c9b88772123f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2501066Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Min Chen <minch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821773}

ash/wm/desks/desk_name_view.cc

@@ -54,8 +54,6 @@ DeskNameView::DeskNameView() {
 
   SetCursorEnabled(true);
   SetHorizontalAlignment(gfx::HorizontalAlignment::ALIGN_CENTER);
-  SetBackground(views::CreateRoundedRectBackground(GetBackgroundColor(),
-                                                   kDeskNameViewBorderRadius));
 }
 
 DeskNameView::~DeskNameView() = default;
@@ -129,6 +127,8 @@ void DeskNameView::OnMouseExited(const ui::MouseEvent& event) {
 
 void DeskNameView::OnThemeChanged() {
   Textfield::OnThemeChanged();
+  SetBackground(views::CreateRoundedRectBackground(GetBackgroundColor(),
+                                                   kDeskNameViewBorderRadius));
   AshColorProvider* color_provider = AshColorProvider::Get();
   const SkColor text_color = color_provider->GetContentLayerColor(
       AshColorProvider::ContentLayerType::kTextColorPrimary);
@@ -138,7 +138,7 @@ void DeskNameView::OnThemeChanged() {
   const SkColor selection_color = color_provider->GetControlsLayerColor(
       AshColorProvider::ControlsLayerType::kFocusAuraColor);
   SetSelectionBackgroundColor(selection_color);
-  UpdateViewAppearance();
+  UpdateBorderState();
 }
 
 views::View* DeskNameView::GetView() {