Implement timestamp translation/filter in VideoCapturer.

webrtc/media/base/fakevideocapturer.h

 /*
  *  Copyright (c) 2004 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 133 matching lines @@
     fourccs->push_back(cricket::FOURCC_MJPG);
     return true;
   }
 
   void SetRotation(webrtc::VideoRotation rotation) {
     rotation_ = rotation;
   }
 
   webrtc::VideoRotation GetRotation() { return rotation_; }
 
+  // Expose as public, for testing.
+  using VideoCapturer::AdaptFrame;
+  using VideoCapturer::clip_bias_us;
+
  private:
   bool running_;
   int64_t initial_timestamp_;
   int64_t next_timestamp_;
   const bool is_screencast_;
   webrtc::VideoRotation rotation_;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_BASE_FAKEVIDEOCAPTURER_H_