Make base::Timer sequence-friendly.

content/browser/loader/upload_progress_tracker.cc

Index: content/browser/loader/upload_progress_tracker.cc
diff --git a/content/browser/loader/upload_progress_tracker.cc b/content/browser/loader/upload_progress_tracker.cc
index 6633e61b7ec89abd148cd6249f49496b0ad24f25..f9fe05ba04ad43c8be94b72c60bc255c70016744 100644
--- a/content/browser/loader/upload_progress_tracker.cc
+++ b/content/browser/loader/upload_progress_tracker.cc
@@ -19,7 +19,7 @@ UploadProgressTracker::UploadProgressTracker(
     const tracked_objects::Location& location,
     UploadProgressReportCallback report_progress,
     net::URLRequest* request,
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner)
+    scoped_refptr<base::SequencedTaskRunner> task_runner)
     : request_(request), report_progress_(std::move(report_progress)) {
   DCHECK(report_progress_);
 
@@ -40,6 +40,11 @@ void UploadProgressTracker::OnUploadCompleted() {
   progress_timer_.Stop();
 }
 
+// static
+base::TimeDelta UploadProgressTracker::GetUploadProgressIntervalForTesting() {
+  return kUploadProgressInterval;
+}
+
 base::TimeTicks UploadProgressTracker::GetCurrentTime() const {
   return base::TimeTicks::Now();
 }