Don't reset scroll position of contents on every ScrollView layout.

ash/common/system/tray/tray_details_view.cc

 // Copyright (c) 2012 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/common/system/tray/tray_details_view.h"
 
 #include "ash/common/ash_view_ids.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/system/tray/fixed_sized_scroll_view.h"
 #include "ash/common/system/tray/system_menu_button.h"
@@ skipping 466 matching lines @@
       this, SystemMenuButton::InkDropStyle::SQUARE, kSystemMenuArrowBackIcon,
       IDS_ASH_STATUS_TRAY_PREVIOUS_MENU);
   return button;
 }
 
 void TrayDetailsView::Layout() {
   if (UseMd()) {
     views::View::Layout();
     if (scroller_ && !scroller_->is_bounded())
       scroller_->ClipHeightTo(0, scroller_->height());
+    return;
   }
 
-  if (UseMd() || bounds().IsEmpty()) {
+  if (bounds().IsEmpty()) {
     views::View::Layout();
     return;
   }
 
   if (scroller_) {
     scroller_->set_fixed_size(gfx::Size());
     gfx::Size size = GetPreferredSize();
 
     // Set the scroller to fill the space above the bottom row, so that the
     // bottom row of the detailed view will always stay just above the title
@@ skipping 30 matching lines @@
     if (index < child_count() - 1 && child_at(index + 1) != title_row_)
       scroll_border_->set_visible(true);
     else
       scroll_border_->set_visible(false);
   }
 
   views::View::OnPaintBorder(canvas);
 }
 
 }  // namespace ash