[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.

[sadrul, 2016/12/14 00:48:28]

Is this taken care of elsewhere? Or do we not want this UX anymore?

[varkha, 2016/12/14 17:46:42]

No, we don't want this anymore. The connected VPN will be the top item in the
top section because of the logic around line 485 in this file. So bubbling it
out of sticky sections was superficial.

-    AddNetwork(networks.front());
-    networks.erase(networks.begin());
-  }
-
   // Show all VPN providers and all networks that are currently disconnected.
   AddProvidersAndNetworks(networks);