Hide mouse cursor when screenshot is taking

chrome/browser/ui/ash/chrome_screenshot_grabber.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 "chrome/browser/ui/ash/chrome_screenshot_grabber.h"
 
 #include <stddef.h>
 
 #include "ash/common/system/system_notifier.h"
 #include "ash/shell.h"
@@ skipping 359 matching lines @@
         base::Bind(&EnsureDirectoryExistsCallback, callback, profile, path));
     return;
   }
   ui::ScreenshotGrabberDelegate::PrepareFileAndRunOnBlockingPool(
       path, blocking_task_runner, callback);
 }
 
 void ChromeScreenshotGrabber::OnScreenshotCompleted(
     ui::ScreenshotGrabberObserver::Result result,
     const base::FilePath& screenshot_path) {
+  // Cursor is hidden during the screenshot. Show it when screenshot completed.
+  ash::Shell* shell = ash::Shell::GetInstance();
+  if (shell->cursor_manager())
+    shell->cursor_manager()->ShowCursor();

[sky, 2016/07/21 19:40:26]

Why is the show here and not in ScreenshotGrabber? I would expect the place
doing the hide to also do the show. To do otherwise is error prone. Also please
put the calls to show/hide in the same object that is easy to reason about
lifetime. See ScopedCursorHider in aura/window for what I mean.

[Qiang(Joe) Xu, 2016/07/21 23:02:49]

Thanks, based on the suggestion I got a updated version.

   // Do not show a notification that a screenshot was taken while no user is
   // logged in, since it is confusing for the user to get a message about it
   // after he logs in (crbug.com/235217).
   if (!chromeos::LoginState::Get()->IsUserLoggedIn())
     return;
 
   // TODO(sschmitz): make this work for Windows.
   NotifierStateTracker* const notifier_state_tracker =
       NotifierStateTrackerFactory::GetForProfile(GetProfile());
   if (notifier_state_tracker->IsNotifierEnabled(message_center::NotifierId(
@@ skipping 39 matching lines @@
 }
 
 void ChromeScreenshotGrabber::SetProfileForTest(Profile* profile) {
   profile_for_test_ = profile;
 }
 
 Profile* ChromeScreenshotGrabber::GetProfile() {
   return profile_for_test_ ? profile_for_test_
                            : ProfileManager::GetActiveUserProfile();
 }