Use TaskScheduler instead of blocking pool in chrome_screenshot_grabber.cc.

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/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/system_notifier.h"
 #include "base/base64.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_util.h"
 #include "base/i18n/time_formatting.h"
 #include "base/macros.h"
 #include "base/metrics/user_metrics.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chromeos/drive/file_system_util.h"
 #include "chrome/browser/chromeos/file_manager/open_util.h"
 #include "chrome/browser/chromeos/note_taking_helper.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/notifications/notifier_state_tracker.h"
 #include "chrome/browser/notifications/notifier_state_tracker_factory.h"
@@ skipping 34 matching lines @@
     ui::ScopedClipboardWriter scw(ui::CLIPBOARD_TYPE_COPY_PASTE);
     std::string html(kImageClipboardFormatPrefix);
     html += encoded;
     html += kImageClipboardFormatSuffix;
     scw.WriteHTML(base::UTF8ToUTF16(html), std::string());
   }
   base::RecordAction(base::UserMetricsAction("Screenshot_CopyClipboard"));
 }
 
 void ReadFileAndCopyToClipboardLocal(const base::FilePath& screenshot_path) {
-  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
-
   scoped_refptr<base::RefCountedString> png_data(new base::RefCountedString());
   if (!base::ReadFileToString(screenshot_path, &(png_data->data()))) {
     LOG(ERROR) << "Failed to read the screenshot file: "
                << screenshot_path.value();
     return;
   }
 
   content::BrowserThread::PostTask(
       content::BrowserThread::UI, FROM_HERE,
       base::Bind(CopyScreenshotToClipboard, png_data));
@@ skipping 187 matching lines @@
   }
 
   return file_name;
 }
 
 }  // namespace
 
 ChromeScreenshotGrabber::ChromeScreenshotGrabber()
     : screenshot_grabber_(new ui::ScreenshotGrabber(
           this,
-          content::BrowserThread::GetBlockingPool()
-              ->GetTaskRunnerWithShutdownBehavior(
-                  base::SequencedWorkerPool::SKIP_ON_SHUTDOWN))),
+          base::CreateTaskRunnerWithTraits(
+              base::TaskTraits()
+                  .MayBlock()
+                  .WithPriority(base::TaskPriority::BACKGROUND)

[James Cook, 2017/04/26 20:46:44]

I think this should be USER_VISIBLE. The user is waiting for the screenshot
notification to appear.

[fdoray, 2017/04/27 13:35:31]

Done.

+                  .WithShutdownBehavior(
+                      base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN)))),
       profile_for_test_(NULL) {
   screenshot_grabber_->AddObserver(this);
 }
 
 ChromeScreenshotGrabber::~ChromeScreenshotGrabber() {
   screenshot_grabber_->RemoveObserver(this);
 }
 
 void ChromeScreenshotGrabber::HandleTakeScreenshotForAllRootWindows() {
   if (ScreenshotsDisabled()) {
@@ skipping 169 matching lines @@
 }
 
 void ChromeScreenshotGrabber::SetProfileForTest(Profile* profile) {
   profile_for_test_ = profile;
 }
 
 Profile* ChromeScreenshotGrabber::GetProfile() {
   return profile_for_test_ ? profile_for_test_
                            : ProfileManager::GetActiveUserProfile();
 }