Factor out upload progress handling from AsyncResourceHandler

content/browser/loader/upload_progress_tracker.h

Index: content/browser/loader/upload_progress_tracker.h
diff --git a/content/browser/loader/upload_progress_tracker.h b/content/browser/loader/upload_progress_tracker.h
new file mode 100644
index 0000000000000000000000000000000000000000..c43731116ce24fcd44e6685ff8cbfb9578a573b4
--- /dev/null
+++ b/content/browser/loader/upload_progress_tracker.h
@@ -0,0 +1,58 @@
+// Copyright 2016 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.
+
+#ifndef CONTENT_BROWSER_LOADER_UPLOAD_PROGRESS_TRACKER_H_
+#define CONTENT_BROWSER_LOADER_UPLOAD_PROGRESS_TRACKER_H_
+
+#include <stdint.h>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+
+namespace tracked_objects {
+class Location;
+}
+
+namespace net {
+class URLRequest;
+}
+
+namespace content {
+
+// UploadProgressTracker watches the upload progress of a URL loading, and sends
+// the progress to the client in a suitable granularity and frequency.
+class UploadProgressTracker final {
+ public:
+  using UploadProgressReportCallback =
+      base::RepeatingCallback<void(int64_t, int64_t)>;
+
+  UploadProgressTracker(UploadProgressReportCallback report_progress,
+                        net::URLRequest* request);
+  ~UploadProgressTracker();
+
+  void OnAckReceived();
+
+  void Start(const tracked_objects::Location& location);
+  void OnUploadCompleted();
+
+ private:
+  void ReportUploadProgressIfNeeded();
+
+  net::URLRequest* request_;  // Not owned.
+
+  uint64_t last_upload_position_ = 0;
+  bool waiting_for_upload_progress_ack_ = false;
+  base::TimeTicks last_upload_ticks_;
+  base::RepeatingTimer progress_timer_;
+
+  UploadProgressReportCallback report_progress_;
+
+  DISALLOW_COPY_AND_ASSIGN(UploadProgressTracker);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_LOADER_UPLOAD_PROGRESS_TRACKER_H_