[ash-md] Stacks child layers properly for sticky header rows

ash/common/system/chromeos/network/vpn_list_view.cc

Index: ash/common/system/chromeos/network/vpn_list_view.cc
diff --git a/ash/common/system/chromeos/network/vpn_list_view.cc b/ash/common/system/chromeos/network/vpn_list_view.cc
index a66d03cac78fead0afe45be525d9334ba1316100..2b22a4fe103d1fe93661a9ea77a870ca9c7ac40f 100644
--- a/ash/common/system/chromeos/network/vpn_list_view.cc
+++ b/ash/common/system/chromeos/network/vpn_list_view.cc
@@ -112,21 +112,11 @@ class VPNListProviderEntryMd : public views::ButtonListener,
                          const std::string& name,
                          int button_accessible_name_id)
       : parent_(parent) {
-    // TODO(varkha): Make this a sticky section header.
+    TrayPopupUtils::ConfigureAsStickyHeader(this);
     SetLayoutManager(new views::FillLayout);
     TriView* tri_view = TrayPopupUtils::CreateSubHeaderRowView();
     AddChildView(tri_view);
 
-    // Sets up the border. When the provider header is the first item in the
-    // list (i.e. when the list was empty before adding the provider row) there
-    // is already |kMenuSeparatorVerticalPadding| padding at the top of the
-    //  scroll contents, so only add that padding when the list was not |empty|.
-    // TODO(varkha): Delete this special handling when we allow the header to be
-    // sticky and just use ConfigureAsStickyHeader() instead.
-    tri_view->SetBorder(
-        views::CreateEmptyBorder(top_item ? 0 : kMenuSeparatorVerticalPadding,
-                                 0, kMenuSeparatorVerticalPadding, 0));
-
     views::Label* label = TrayPopupUtils::CreateDefaultLabel();
     TrayPopupItemStyle style(TrayPopupItemStyle::FontStyle::SUB_HEADER);
     style.SetupLabel(label);
@@ -370,12 +360,6 @@ void VPNListView::Update() {
       ->GetVisibleNetworkListByType(chromeos::NetworkTypePattern::VPN(),
                                     &networks);
 
-  if (!networks.empty() && IsConnectedOrConnecting(networks.front())) {
-    // If there is a connected or connecting network, show that network first.
-    AddNetwork(networks.front());
-    networks.erase(networks.begin());
-  }
-
   // Show all VPN providers and all networks that are currently disconnected.
   AddProvidersAndNetworks(networks);