Add WebrtcCaptureScheduler interface.

remoting/codec/webrtc_video_encoder.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_CODEC_WEBRTC_VIDEO_ENCODER_H_
 #define REMOTING_CODEC_WEBRTC_VIDEO_ENCODER_H_
 
 #include <stdint.h>
 
 #include <memory>
 
 #include "base/time/time.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_geometry.h"
 
 namespace webrtc {
 class DesktopFrame;
 }  // namespace webrtc
 
 namespace remoting {
 
 // A class to perform the task of encoding a continuous stream of images. The
 // interface is asynchronous to enable maximum throughput.
 class WebrtcVideoEncoder {
  public:
   struct FrameParams {
-    int bitrate_kbps;
+    // Target bitrate in kilobits per second.
+    int bitrate_kbps = -1;
+
+    // Frame duration.
     base::TimeDelta duration;
-    bool key_frame;
+
+    // If set to true then the active map passed to the encoder will only
+    // contain updated_region() from the current frame. Otherwise the active map
+    // is not cleared before adding updated_region(), which means it will
+    // contain union of updated_region() from all frames since this flag was
+    // last set. This flag is used to top-off video quality with VP8.
+    bool clear_active_map = false;
+
+    // Indicates that the encoder should encode this frame as a key frame.
+    bool key_frame = false;
+
+    // Quantization parameters for the encoder.
+    int vpx_min_quantizer = -1;
+    int vpx_max_quantizer = -1;
   };
 
   struct EncodedFrame {
     webrtc::DesktopSize size;
     std::string data;
     bool key_frame;
     int quantizer;
   };
 
   virtual ~WebrtcVideoEncoder() {}
 
   // Encode an image stored in |frame|. If |frame.updated_region()| is empty
   // then the encoder may return a packet (e.g. to top-off previously-encoded
   // portions of the frame to higher quality) or return nullptr to indicate that
   // there is no work to do.
   virtual std::unique_ptr<EncodedFrame> Encode(
       const webrtc::DesktopFrame& frame,
       const FrameParams& param) = 0;
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CODEC_WEBRTC_VIDEO_ENCODER_H_