[reland] Use TaskScheduler instead of blocking pool in file_downloader.cc.

chrome/browser/net/file_downloader_unittest.cc

 // 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.
 
 #include "chrome/browser/net/file_downloader.h"
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
-#include "base/message_loop/message_loop.h"
-#include "base/run_loop.h"
-#include "base/threading/sequenced_worker_pool.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
-#include "content/public/browser/browser_thread.h"
+#include "content/public/test/test_utils.h"
 #include "net/traffic_annotation/network_traffic_annotation_test_helper.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 const char kURL[] = "https://www.url.com/path";
 const char kFilename[] = "filename.ext";
 const char kFileContents1[] = "file contents";
@@ skipping 36 matching lines @@
   }
 
   void Download(bool overwrite, FileDownloader::Result expected_result) {
     FileDownloader downloader(
         GURL(kURL), path_, overwrite, request_context_.get(),
         base::Bind(&FileDownloaderTest::OnDownloadFinished,
                    base::Unretained(this)),
         TRAFFIC_ANNOTATION_FOR_TESTS);
     EXPECT_CALL(*this, OnDownloadFinished(expected_result));
     // Wait for the FileExists check to happen if necessary.
-    if (!overwrite)
-      content::BrowserThread::GetBlockingPool()->FlushForTesting();
-    // Wait for the actual download to happen.
-    base::RunLoop().RunUntilIdle();
-    // Wait for the FileMove to happen.
-    content::BrowserThread::GetBlockingPool()->FlushForTesting();
-    base::RunLoop().RunUntilIdle();
+    content::RunAllBlockingPoolTasksUntilIdle();
   }
 
  private:
   base::ScopedTempDir dir_;
   base::FilePath path_;
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   scoped_refptr<net::TestURLRequestContextGetter> request_context_;
   net::FakeURLFetcherFactory url_fetcher_factory_;
 };
 
 TEST_F(FileDownloaderTest, Success) {
   SetValidResponse();
   Download(true, FileDownloader::DOWNLOADED);
   EXPECT_TRUE(base::PathExists(path()));
   std::string contents;
   ASSERT_TRUE(base::ReadFileToString(path(), &contents));
@@ skipping 30 matching lines @@
   ASSERT_TRUE(base::ReadFileToString(path(), &contents));
   EXPECT_EQ(std::string(kFileContents1), contents);
 
   SetValidResponse2();
   Download(false, FileDownloader::EXISTS);
   // The file should still have the old contents.
   EXPECT_TRUE(base::PathExists(path()));
   ASSERT_TRUE(base::ReadFileToString(path(), &contents));
   EXPECT_EQ(std::string(kFileContents1), contents);
 }