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

ash/system/user/user_view.cc

Index: ash/system/user/user_view.cc
diff --git a/ash/system/user/user_view.cc b/ash/system/user/user_view.cc
index fe2ff061c8ceb920ba8c8d8fb6ab226e587c99ae..fb96987cd927ad46fb9072484ed2716bab72ebdc 100644
--- a/ash/system/user/user_view.cc
+++ b/ash/system/user/user_view.cc
@@ -36,6 +36,7 @@
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/paint_vector_icon.h"
+#include "ui/native_theme/native_theme.h"
 #include "ui/views/controls/button/label_button.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/separator.h"
@@ -72,8 +73,7 @@ bool IsMultiProfileSupportedAndUserActive() {
 }
 
 // Creates the view shown in the user switcher popup ("AddUserMenuOption").
-views::View* CreateAddUserView(AddUserSessionPolicy policy,
-                               views::ButtonListener* listener) {
+views::View* CreateAddUserView(AddUserSessionPolicy policy) {
   auto* view = new views::View;
   const int icon_padding = (kMenuButtonSize - kMenuIconSize) / 2;
   auto* layout =
@@ -81,8 +81,8 @@ views::View* CreateAddUserView(AddUserSessionPolicy policy,
                            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) {
@@ -123,13 +123,6 @@ views::View* CreateAddUserView(AddUserSessionPolicy policy,
   view->SetBorder(views::CreateEmptyBorder(vertical_padding, icon_padding,
                                            vertical_padding,
                                            kTrayPopupLabelHorizontalPadding));
-  if (policy == AddUserSessionPolicy::ALLOWED) {
-    auto* button =
-        new ButtonFromView(view, listener, TrayPopupInkDropStyle::INSET_BOUNDS);
-    button->SetAccessibleName(
-        l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_SIGN_IN_ANOTHER_ACCOUNT));
-    return button;
-  }
 
   return view;
 }
@@ -364,14 +357,23 @@ void UserView::ToggleAddUserMenuOption() {
 
   views::View* container = new AddUserWidgetContents(
       base::Bind(&UserView::RemoveAddUserMenuOption, base::Unretained(this)));
+  views::View* add_user_view = CreateAddUserView(add_user_policy);
+  const SkColor bg_color = add_user_view->background()->get_color();
   container->SetBorder(views::CreatePaddedBorder(
-      views::CreateSolidSidedBorder(0, 0, 0, kSeparatorWidth, kBackgroundColor),
+      views::CreateSolidSidedBorder(0, 0, 0, kSeparatorWidth, bg_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->AddChildView(add_user_view);
+      kMenuSeparatorVerticalPadding, 0, 0, 0, bg_color));
+  if (add_user_enabled_) {
+    auto* button = new ButtonFromView(add_user_view, this,
+                                      TrayPopupInkDropStyle::INSET_BOUNDS);
+    button->SetAccessibleName(
+        l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_SIGN_IN_ANOTHER_ACCOUNT));
+    add_user_padding->AddChildView(button);

[Evan Stade, 2017/04/19 18:49:07]

oops, this will break the button pressed handler. note to self: fix before
landing.

+  } else {
+    add_user_padding->AddChildView(add_user_view);
+  }
   add_user_padding->SetLayoutManager(new views::FillLayout());
   container->AddChildView(add_user_padding);
   container->SetLayoutManager(new views::FillLayout());