Fix integration tests in src/chrome and src/extensions so that we can turn on IO thread checks wi...

chrome/browser/extensions/api/image_writer_private/image_writer_utility_client_browsertest.cc

 // Copyright 2017 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/extensions/api/image_writer_private/image_writer_utility_client.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/task_scheduler/post_task.h"
+#include "base/threading/thread_restrictions.h"
 #include "chrome/common/extensions/removable_storage_writer.mojom.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "content/public/browser/browser_thread.h"
 
 constexpr int64_t kTestFileSize = 1 << 15;  // 32 kB
 
 class ImageWriterUtilityClientTest : public InProcessBrowserTest {
  public:
   ImageWriterUtilityClientTest() {
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
     test_device_ = base::FilePath().AppendASCII(
         extensions::mojom::RemovableStorageWriter::kTestDevice);
     EXPECT_TRUE(temp_dir_.CreateUniqueTempDir());
   }
 
   void FillImageFileWithPattern(char pattern) {
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
     EXPECT_TRUE(base::CreateTemporaryFileInDir(temp_dir_.GetPath(), &image_));
 
     base::RunLoop run_loop;
     base::PostTaskWithTraitsAndReply(
         FROM_HERE, base::TaskTraits().MayBlock(),
         base::Bind(&ImageWriterUtilityClientTest::FillFile, image_, pattern),
         run_loop.QuitClosure());
 
     run_loop.Run();
   }
@@ skipping 268 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(ImageWriterUtilityClientTest, VerifyCancel) {
   FillImageFileWithPattern('s');
   FillDeviceFileWithPattern('s');
 
   RunVerifyTest(CANCEL);
 
   EXPECT_TRUE(success());
   EXPECT_TRUE(error().empty());
 }