Use base::GetContinuationTaskRunner() instead of base::SequencedTaskRunnerHandle::Get()

The latter is deprecated, and doesn't seem to support thread pool
environment. So switching to the former.

BUG=1009839

Change-Id: Ieef5e65b6220d46cd262f1550324f8636dbeb68d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1918221
Commit-Queue: Min Qin <qinmin@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715802}

components/download/internal/common/download_file_impl.cc

@@ -11,8 +11,7 @@
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/strings/stringprintf.h"
-#include "base/threading/sequenced_task_runner_handle.h"
-#include "base/threading/thread_task_runner_handle.h"
+#include "base/task/post_task.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "base/values.h"
@@ -194,6 +193,8 @@ void DownloadFileImpl::Initialize(
   int64_t bytes_so_far = 0;
   cancel_request_callback_ = cancel_request_callback;
   received_slices_ = received_slices;
+  if (!task_runner_)
+    task_runner_ = base::GetContinuationTaskRunner();
 
   // If the last slice is finished, then we know the actual content size.
   if (!received_slices_.empty() && received_slices_.back().finished) {
@@ -451,7 +452,7 @@ void DownloadFileImpl::RenameWithRetryInternal(
     --parameters->retries_left;
     if (parameters->time_of_first_failure.is_null())
       parameters->time_of_first_failure = base::TimeTicks::Now();
-    base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
+    task_runner_->PostDelayedTask(
         FROM_HERE,
         base::BindOnce(&DownloadFileImpl::RenameWithRetryInternal,
                        weak_factory_.GetWeakPtr(), std::move(parameters)),
@@ -631,7 +632,7 @@ void DownloadFileImpl::StreamActive(SourceStream* source_stream,
   // If we're stopping to yield the thread, post a task so we come back.
   if (state == InputStream::HAS_DATA && now - start > delta &&
       !should_terminate) {
-    base::SequencedTaskRunnerHandle::Get()->PostTask(
+    task_runner_->PostTask(
         FROM_HERE, base::BindOnce(&DownloadFileImpl::StreamActive,
                                   weak_factory_.GetWeakPtr(), source_stream,
                                   MOJO_RESULT_OK));
@@ -911,6 +912,11 @@ void DownloadFileImpl::DebugStates() const {
   DebugSlicesInfo(received_slices_);
 }
 
+void DownloadFileImpl::SetTaskRunnerForTesting(
+    scoped_refptr<base::SequencedTaskRunner> task_runner) {
+  task_runner_ = std::move(task_runner);
+}
+
 DownloadFileImpl::RenameParameters::RenameParameters(
     RenameOption option,
     const base::FilePath& new_path,

components/download/internal/common/download_file_unittest.cc

@@ -258,6 +258,8 @@ class DownloadFileTest : public testing::Test {
     base::WeakPtrFactory<DownloadFileTest> weak_ptr_factory(this);
     DownloadInterruptReason result = DOWNLOAD_INTERRUPT_REASON_NONE;
     base::RunLoop loop_runner;
+    download_file_->SetTaskRunnerForTesting(
+        base::SequencedTaskRunnerHandle::Get());
     download_file_->Initialize(
         base::BindRepeating(&DownloadFileTest::SetInterruptReasonCallback,
                             weak_ptr_factory.GetWeakPtr(),

components/download/internal/common/stream_handle_input_stream.cc

@@ -5,6 +5,7 @@
 #include "components/download/public/common/stream_handle_input_stream.h"
 
 #include "base/bind.h"
+#include "base/task/post_task.h"
 #include "components/download/public/common/download_interrupt_reasons_utils.h"
 #include "mojo/public/c/system/types.h"
 
@@ -34,7 +35,7 @@ void StreamHandleInputStream::Initialize() {
       mojom::NetworkRequestStatus::USER_CANCELED));
   handle_watcher_ = std::make_unique<mojo::SimpleWatcher>(
       FROM_HERE, mojo::SimpleWatcher::ArmingPolicy::AUTOMATIC,
-      base::SequencedTaskRunnerHandle::Get());
+      base::GetContinuationTaskRunner());
 }
 
 bool StreamHandleInputStream::IsEmpty() {

components/download/public/common/download_file_impl.h

@@ -190,6 +190,11 @@ class COMPONENTS_DOWNLOAD_EXPORT DownloadFileImpl : public DownloadFile {
     DISALLOW_COPY_AND_ASSIGN(SourceStream);
   };
 
+  // Sets the task runner for testing purpose, must be called before
+  // Initialize().
+  void SetTaskRunnerForTesting(
+      scoped_refptr<base::SequencedTaskRunner> task_runner);
+
  protected:
   // For test class overrides.
   // Validate the first |bytes_to_validate| bytes and write the next
@@ -374,6 +379,9 @@ class COMPONENTS_DOWNLOAD_EXPORT DownloadFileImpl : public DownloadFile {
   // TaskRunner to post updates to the |observer_|.
   scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
 
+  // TaskRunner this object lives on after initialization.
+  scoped_refptr<base::SequencedTaskRunner> task_runner_;
+
 #if defined(OS_ANDROID)
   base::FilePath display_name_;
 #endif  // defined(OS_ANDROID)