Remove non-MD code from TrayBackgroundView

ash/common/system/chromeos/palette/palette_tray.cc

 // Copyright 2016 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/palette/palette_tray.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 132 matching lines @@
   views::View* settings_button_;
   views::View* help_button_;
   PaletteTray* palette_tray_;
 
   DISALLOW_COPY_AND_ASSIGN(TitleView);
 };
 
 }  // namespace
 
 PaletteTray::PaletteTray(WmShelf* wm_shelf)
-    : TrayBackgroundView(wm_shelf),
+    : TrayBackgroundView(wm_shelf, true),
       palette_tool_manager_(new PaletteToolManager(this)),
       weak_factory_(this) {
   PaletteTool::RegisterToolInstances(palette_tool_manager_.get());
 
-  if (MaterialDesignController::IsShelfMaterial()) {
+  if (MaterialDesignController::IsShelfMaterial())
     SetInkDropMode(InkDropMode::ON);
-    SetContentsBackground(false);
-  } else {
-    SetContentsBackground(true);
-  }
 
   SetLayoutManager(new views::FillLayout());
   icon_ = new views::ImageView();
   UpdateTrayIcon();
 
   tray_container()->SetMargin(kTrayIconMainAxisInset, kTrayIconCrossAxisInset);
   tray_container()->AddChildView(icon_);
 
   Shell::GetInstance()->AddShellObserver(this);
   WmShell::Get()->GetSessionStateDelegate()->AddSessionStateObserver(this);
@@ skipping 254 matching lines @@
     UpdateIconVisibility();
   }
 }
 
 void PaletteTray::UpdateIconVisibility() {
   SetVisible(is_palette_enabled_ && palette_utils::HasStylusInput() &&
              IsInUserSession());
 }
 
 }  // namespace ash