Do not use assets for Ash window control button backgrounds

ash/frame/custom_frame_view_ash_unittest.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/frame/custom_frame_view_ash.h"
 
 #include "ash/frame/caption_buttons/frame_caption_button.h"
 #include "ash/frame/caption_buttons/frame_caption_button_container_view.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
@@ skipping 110 matching lines @@
 };
 
 // Test that the height of the header is correct upon initially displaying
 // the widget.
 TEST_F(CustomFrameViewAshTest, HeaderHeight) {
   TestWidgetDelegate* delegate = new TestWidgetDelegate;
 
   scoped_ptr<views::Widget> widget(CreateWidget(delegate));
   widget->Show();
 
-  ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
-  gfx::ImageSkia* close_button =
-      rb.GetImageSkiaNamed(IDR_AURA_WINDOW_CONTROL_BACKGROUND_H);
-
   // The header should have enough room for the window controls. The
   // header/content separator line overlays the window controls.
-  EXPECT_EQ(close_button->height(),
-            delegate->custom_frame_view()->GetHeaderView()->height());
+  EXPECT_EQ(33, delegate->custom_frame_view()->GetHeaderView()->height());
 }
 
 // Verify that CustomFrameViewAsh returns the correct minimum and maximum frame
 // sizes when the client view does not specify any size constraints.
 TEST_F(CustomFrameViewAshTest, NoSizeConstraints) {
   TestWidgetConstraintsDelegate* delegate = new TestWidgetConstraintsDelegate;
   scoped_ptr<views::Widget> widget(CreateWidget(delegate));
 
   CustomFrameViewAsh* custom_frame_view = delegate->custom_frame_view();
   gfx::Size min_frame_size = custom_frame_view->GetMinimumSize();
@@ skipping 71 matching lines @@
   EXPECT_GT(initial.width(), maximize_mode_bounds.width());
   Shell::GetInstance()->maximize_mode_controller()->
       EnableMaximizeModeWindowManager(false);
   delegate->EndFrameCaptionButtonContainerViewAnimations();
   const gfx::Rect after_restore = delegate->
       GetFrameCaptionButtonContainerViewBounds();
   EXPECT_EQ(initial, after_restore);
 }
 
 }  // namespace ash