UMA stats for stylus usage

chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl.h

 // Copyright 2013 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.
 
 #ifndef CHROME_BROWSER_UI_ASH_LAUNCHER_CHROME_LAUNCHER_CONTROLLER_IMPL_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_CHROME_LAUNCHER_CONTROLLER_IMPL_H_
 
 #include <list>
 #include <memory>
 
 #include "ash/common/shelf/shelf_delegate.h"
 #include "ash/common/shelf/shelf_model_observer.h"
 #include "ash/common/shelf/shelf_types.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "build/build_config.h"
 #include "chrome/browser/ui/app_icon_loader.h"
 #include "chrome/browser/ui/app_list/app_list_syncable_service.h"
 #include "chrome/browser/ui/ash/app_sync_ui_state_observer.h"
 #include "chrome/browser/ui/ash/launcher/chrome_launcher_controller.h"
 #include "chrome/browser/ui/ash/launcher/launcher_app_updater.h"
+#include "chrome/browser/ui/ash/metrics/stylus_metrics_recorder.h"

[sky, 2016/09/13 00:03:25]

Only include this if on chromeos (to match your ifdef below).

[xiaoyinh(OOO Sep 11-29), 2016/09/16 18:41:16]

Done.

 #include "components/prefs/pref_change_registrar.h"
 #include "ui/aura/window_observer.h"
 
 class AppSyncUIState;
 class BrowserStatusMonitor;
 class LauncherControllerHelper;
 class Profile;
 class AppWindowLauncherController;
 class TabContents;
 
@@ skipping 327 matching lines @@
 
   // If true, incoming pinned state changes should be ignored.
   bool ignore_persist_pinned_state_change_ = false;
 
   // The list of running & un-pinned applications for different users on hidden
   // desktops.
   typedef std::vector<std::string> RunningAppListIds;
   typedef std::map<std::string, RunningAppListIds> RunningAppListIdMap;
   RunningAppListIdMap last_used_running_application_order_;
 
+#if defined(OS_CHROMEOS)
+  // Record stylus metrics for down event.
+  std::unique_ptr<chromeos::StylusMetricsRecorder> stylus_metrics_recorder_;
+#endif
+
   base::WeakPtrFactory<ChromeLauncherControllerImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeLauncherControllerImpl);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_CHROME_LAUNCHER_CONTROLLER_IMPL_H_