Add WebrtcCaptureScheduler interface.

remoting/protocol/webrtc_frame_scheduler_simple.h

+// 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 REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_
+#define REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_
+
+#include "remoting/protocol/webrtc_frame_scheduler.h"
+
+#include "base/timer/timer.h"
+
+namespace remoting {
+namespace protocol {
+
+// WebrtcFrameSchedulerSimple is a simple implementation of
+// WebrtcFrameScheduler that always keeps only one frame in the pipeline.
+// It schedules each frame after the previous one is expected to finish sending.
+class WebrtcFrameSchedulerSimple : public WebrtcFrameScheduler {
+ public:
+  WebrtcFrameSchedulerSimple();
+  ~WebrtcFrameSchedulerSimple() override;
+
+  // WebrtcFrameScheduler implementation.
+  void Start(const base::Closure& capture_callback) override;
+  void Pause(bool pause) override;
+  void SetKeyFrameRequest() override;
+  void SetTargetBitrate(int bitrate_kbps) override;
+  bool GetEncoderFrameParams(
+      const webrtc::DesktopFrame& frame,
+      WebrtcVideoEncoder::FrameParams* params_out) override;
+  void OnFrameEncoded(
+      const WebrtcVideoEncoder::EncodedFrame& encoded_frame,
+      const webrtc::EncodedImageCallback::Result& send_result) override;
+
+ private:
+  void ScheduleNextFrame();
+  void CaptureNextFrame();
+
+  base::Closure capture_callback_;
+  bool paused_ = false;
+  bool key_frame_request_ = false;
+  uint32_t target_bitrate_kbps_ = 1000;  // Initial bitrate.
+
+  base::TimeTicks last_capture_started_time_;
+  base::TimeTicks last_frame_send_finish_time_;
+
+  // Set to true when encoding unchanged frames for top-off.
+  bool top_off_is_active_ = false;
+
+  base::OneShotTimer capture_timer_;
+};
+
+}  // namespace protocol
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_