Consolidate some more ash tray constants.

ash/common/system/chromeos/audio/volume_view.cc

 // Copyright 2014 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/chromeos/audio/volume_view.h"
 
 #include <algorithm>
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/metrics/user_metrics_action.h"
@@ skipping 167 matching lines @@
     Update();
     return;
   }
 
   more_button_ = new ButtonListenerActionableView(
       owner_, TrayPopupInkDropStyle::INSET_BOUNDS, this);
   TrayPopupUtils::ConfigureContainer(TriView::Container::END, more_button_);
   more_button_->SetFocusBehavior(FocusBehavior::NEVER);
 
   device_type_ = TrayPopupUtils::CreateMoreImageView();
-  more_button_->SetBorder(views::CreateEmptyBorder(gfx::Insets(
-      0, GetTrayConstant(TRAY_POPUP_ITEM_MORE_REGION_HORIZONTAL_INSET))));
+  more_button_->SetBorder(
+      views::CreateEmptyBorder(gfx::Insets(0, kTrayPopupButtonEndMargin)));

[tdanderson, 2017/02/28 17:08:18]

nit: consider renaming to kTrayPopupButtonHorizontalMargin /  or similar and
update the documentation in tray_constants.h

[Evan Stade, 2017/03/01 04:28:54]

I removed the docs, but horizontal margin is just as problematic as end margin
since in other places it's only applied to the end (right).

   more_button_->AddChildView(device_type_);
 
   views::ImageView* more_arrow = TrayPopupUtils::CreateMoreImageView();
   if (MaterialDesignController::IsSystemTrayMenuMaterial()) {
     more_arrow->SetImage(
         gfx::CreateVectorIcon(kSystemMenuArrowRightIcon, kMenuIconColor));
   } else {
     more_arrow->SetImage(ui::ResourceBundle::GetSharedInstance()
                              .GetImageNamed(IDR_AURA_UBER_TRAY_MORE)
                              .ToImageSkia());
@@ skipping 144 matching lines @@
 void VolumeView::OnBoundsChanged(const gfx::Rect& previous_bounds) {
   // Separator's prefered size is based on set bounds. When an empty bounds is
   // set on first layout this causes BoxLayout to ignore the separator. Reset
   // its height on each bounds change so that it is laid out properly.
   if (separator_)
     separator_->SetSize(gfx::Size(kSeparatorSize, bounds().height()));
 }
 
 }  // namespace tray
 }  // namespace ash