Introduce a type of View background that stays in sync with its host

ash/system/user/user_view.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/system/user/user_view.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "ash/multi_profile_uma.h"
@@ skipping 63 matching lines @@
 // Creates the view shown in the user switcher popup ("AddUserMenuOption").
 views::View* CreateAddUserView(AddUserSessionPolicy policy,
                                views::ButtonListener* listener) {
   auto* view = new views::View;
   const int icon_padding = (kMenuButtonSize - kMenuIconSize) / 2;
   auto* layout =
       new views::BoxLayout(views::BoxLayout::kHorizontal, 0, 0,
                            kTrayPopupLabelHorizontalPadding + icon_padding);
   layout->set_minimum_cross_axis_size(kTrayPopupItemMinHeight);
   view->SetLayoutManager(layout);
-  view->set_background(
-      views::Background::CreateSolidBackground(kBackgroundColor));
+  view->set_background(views::Background::CreateThemedSolidBackground(
+      view, ui::NativeTheme::kColorId_BubbleBackground));
 
   int message_id = 0;
   switch (policy) {
     case AddUserSessionPolicy::ALLOWED: {
       message_id = IDS_ASH_STATUS_TRAY_SIGN_IN_ANOTHER_ACCOUNT;
 
       auto* icon = new views::ImageView();
       icon->SetImage(
           gfx::CreateVectorIcon(kSystemMenuNewUserIcon, kMenuIconColor));
       view->AddChildView(icon);
@@ skipping 261 matching lines @@
 
   // Position the widget on top of the user card view (which is still in the
   // system menu). The top half of the widget will be transparent to allow
   // the active user to show through.
   gfx::Rect bounds = user_card_view_->GetBoundsInScreen();
   bounds.set_width(bounds.width() + kSeparatorWidth);
   int row_height = bounds.height();
 
   views::View* container = new AddUserWidgetContents(
       base::Bind(&UserView::RemoveAddUserMenuOption, base::Unretained(this)));
+  views::View* add_user_view = CreateAddUserView(add_user_policy, this);
   container->SetBorder(views::CreatePaddedBorder(
-      views::CreateSolidSidedBorder(0, 0, 0, kSeparatorWidth, kBackgroundColor),
+      views::CreateSolidSidedBorder(0, 0, 0, kSeparatorWidth,
+                                    add_user_view->background()->get_color()),
       gfx::Insets(row_height, 0, 0, 0)));
   views::View* add_user_padding = new views::View();
-  add_user_padding->SetBorder(views::CreateSolidSidedBorder(
-      kMenuSeparatorVerticalPadding, 0, 0, 0, kBackgroundColor));
-  views::View* add_user_view = CreateAddUserView(add_user_policy, this);
+  add_user_padding->SetBorder(
+      views::CreateSolidSidedBorder(kMenuSeparatorVerticalPadding, 0, 0, 0,
+                                    add_user_view->background()->get_color()));
   add_user_padding->AddChildView(add_user_view);
   add_user_padding->SetLayoutManager(new views::FillLayout());
   container->AddChildView(add_user_padding);
   container->SetLayoutManager(new views::FillLayout());
   add_menu_option_->SetContentsView(container);
 
   bounds.set_height(container->GetPreferredSize().height());
   add_menu_option_->SetBounds(bounds);
 
   // Show the content.
@@ skipping 12 matching lines @@
     return;
   focus_manager_->RemoveFocusChangeListener(this);
   focus_manager_ = nullptr;
   if (user_card_view_->GetFocusManager())
     user_card_view_->GetFocusManager()->ClearFocus();
   add_menu_option_.reset();
 }
 
 }  // namespace tray
 }  // namespace ash