Reduce CPU usage of download shelf UI. (both MD and pre-MD shelves)

chrome/browser/ui/views/download/download_item_view_md.h

 // Copyright 2015 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.
 //
 // A view that implements one download on the Download shelf.
 // Each DownloadItemViewMd contains an application icon, a text label
 // indicating the download's file name, a text label indicating the
 // download's status (such as the number of bytes downloaded so far)
 // and a button for canceling an in progress download, or opening
 // the completed download.
@@ skipping 252 matching lines @@
   // A model class to control the status text we display.
   DownloadItemModel model_;
 
   // Hover animations for our body and drop buttons.
   scoped_ptr<gfx::SlideAnimation> body_hover_animation_;
   scoped_ptr<gfx::SlideAnimation> drop_hover_animation_;
 
   // Animation for download complete.
   scoped_ptr<gfx::SlideAnimation> complete_animation_;
 
-  // Progress animation
-  base::RepeatingTimer progress_timer_;
-
   // Dangerous mode buttons.
   views::LabelButton* save_button_;
   views::LabelButton* discard_button_;
 
   // The drop down button.
   BarControlButton* dropdown_button_;
 
   // Dangerous mode label.
   views::Label* dangerous_download_label_;
 
@@ skipping 28 matching lines @@
   scoped_ptr<extensions::ExperienceSamplingEvent> sampling_event_;
 
   // Method factory used to delay reenabling of the item when opening the
   // downloaded file.
   base::WeakPtrFactory<DownloadItemViewMd> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemViewMd);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_DOWNLOAD_DOWNLOAD_ITEM_VIEW_MD_H_