Show small notification icons in notification tray

ash/common/system/tray/tray_background_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_background_view.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/shelf/wm_shelf_util.h"
@@ skipping 168 matching lines @@
   if (size_.IsEmpty())
     return views::View::GetPreferredSize();
   return size_;
 }
 
 void TrayBackgroundView::TrayContainer::ChildPreferredSizeChanged(
     views::View* child) {
   PreferredSizeChanged();
 }
 
+gfx::Insets TrayBackgroundView::TrayContainer::GetInsets() const {
+  return views::View::GetInsets() + insets_;

[xiyuan, 2016/08/05 16:18:59]

Can we use |insets_| and create a proper empty border in
TrayContainer::UpdateLayout instead?

[yoshiki, 2016/08/09 16:43:04]

Done.

+}
+
 void TrayBackgroundView::TrayContainer::ChildVisibilityChanged(View* child) {
   PreferredSizeChanged();
 }
 
 void TrayBackgroundView::TrayContainer::ViewHierarchyChanged(
     const ViewHierarchyChangedDetails& details) {
   if (details.parent == this)
     PreferredSizeChanged();
 }
 
@@ skipping 300 matching lines @@
 }
 
 void TrayBackgroundView::UpdateShelfItemBackground(int alpha) {
   if (background_) {
     background_->set_alpha(alpha);
     SchedulePaint();
   }
 }
 
 }  // namespace ash