Add new UMA stats to get a handle on Downloads UI Usage

chrome/browser/ui/gtk/download/download_shelf_gtk.cc

 // Copyright (c) 2011 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 "chrome/browser/ui/gtk/download/download_shelf_gtk.h"
 
 #include <string>
 
 #include "chrome/browser/download/download_item_model.h"
 #include "chrome/browser/download/download_util.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/gtk/browser_window_gtk.h"
 #include "chrome/browser/ui/gtk/custom_button.h"
 #include "chrome/browser/ui/gtk/download/download_item_gtk.h"
 #include "chrome/browser/ui/gtk/gtk_chrome_link_button.h"
 #include "chrome/browser/ui/gtk/gtk_chrome_shrinkable_hbox.h"
 #include "chrome/browser/ui/gtk/gtk_theme_service.h"
 #include "chrome/browser/ui/gtk/gtk_util.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/browser/download/download_item.h"
+#include "content/browser/download/download_stats.h"
 #include "content/common/notification_service.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
 #include "grit/theme_resources_standard.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/gtk_util.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/point.h"
@@ skipping 156 matching lines @@
   browser_->UpdateDownloadShelfVisibility(true);
   CancelAutoClose();
 }
 
 void DownloadShelfGtk::Close() {
   // When we are closing, we can vertically overlap the render view. Make sure
   // we are on top.
   gdk_window_raise(shelf_.get()->window);
   slide_widget_->Close();
   browser_->UpdateDownloadShelfVisibility(false);
+  download_stats::RecordShelfSize(download_items_.size());
   SetCloseOnMouseOut(false);
 }
 
 Browser* DownloadShelfGtk::browser() const {
   return browser_;
 }
 
 void DownloadShelfGtk::Closed() {
   // When the close animation is complete, remove all completed downloads.
   size_t i = 0;
@@ skipping 162 matching lines @@
 
   MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       auto_close_factory_.NewRunnableMethod(&DownloadShelfGtk::Close),
       kAutoCloseDelayMs);
 }
 
 void DownloadShelfGtk::MouseEnteredShelf() {
   auto_close_factory_.RevokeAll();
 }