Change rtc::VideoSinkWants to have target and a max pixel count

webrtc/media/base/videoadapter.h

 /*
  *  Copyright (c) 2010 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 30 matching lines @@
                             int* out_height);
 
   // Requests the output frame size and frame interval from
   // |AdaptFrameResolution| to not be larger than |format|. Also, the input
   // frame size will be cropped to match the requested aspect ratio. The
   // requested aspect ratio is orientation agnostic and will be adjusted to
   // maintain the input orientation, so it doesn't matter if e.g. 1280x720 or
   // 720x1280 is requested.
   void OnOutputFormatRequest(const VideoFormat& format);
 
-  // Requests the output frame size from |AdaptFrameResolution| to not have
-  // more than |max_pixel_count| pixels and have "one step" up more pixels than
-  // max_pixel_count_step_up.
-  void OnResolutionRequest(rtc::Optional<int> max_pixel_count,
-                           rtc::Optional<int> max_pixel_count_step_up);
+  // Requests the output frame size from |AdaptFrameResolution| to have as close
+  // as possible to |target_pixel_count|, but no more than |max_pixel_count|
+  // pixels. If |target_pixel_count| is not set, treat it as being equal to
+  // |max_pixel_count|. If |max_pixel_count| is not set, treat is as being the
+  // highest resolution available.
+  void OnResolutionRequest(rtc::Optional<int> target_pixel_count,
+                           rtc::Optional<int> max_pixel_count);

[kthelgason, 2017/02/06 12:13:20]

Maybe we should use this opportunity and change these arguments to just const
int*?

From the rtc::Optional docstring:
When you want to pass a value of a
type T that can fail to be there, const T* is almost always both fastest and
cleanest. (If you're *sure* that the the caller will always already have an
Optional<T>, const Optional<T>& is slightly faster than const T*, but this is a
micro-optimization. In general, stick to const T*.)

[sprang_webrtc, 2017/02/06 13:18:07]

Since we're always gonna have an rtc::Optional in the sink wants, I think we
should stick to that.
I will however change this method to accept const rtc::Optional<int>& instead.
Didn't even notice it wasn't already so.

 
  private:
   // Determine if frame should be dropped based on input fps and requested fps.
   bool KeepFrame(int64_t in_timestamp_ns);
 
   int frames_in_;         // Number of input frames.
   int frames_out_;        // Number of output frames.
   int frames_scaled_;     // Number of frames scaled.
   int adaption_changes_;  // Number of changes in scale factor.
   int previous_width_;    // Previous adapter output width.
   int previous_height_;   // Previous adapter output height.
   // Resolution must be divisible by this factor.
   const int required_resolution_alignment_;
   // The target timestamp for the next frame based on requested format.
   rtc::Optional<int64_t> next_frame_timestamp_ns_ GUARDED_BY(critical_section_);
 
   // Max number of pixels requested via calls to OnOutputFormatRequest,
   // OnResolutionRequest respectively.
   // The adapted output format is the minimum of these.
   rtc::Optional<VideoFormat> requested_format_ GUARDED_BY(critical_section_);
+  int resolution_request_target_pixel_count_ GUARDED_BY(critical_section_);
   int resolution_request_max_pixel_count_ GUARDED_BY(critical_section_);
-  bool step_up_ GUARDED_BY(critical_section_);
 
   // The critical section to protect the above variables.
   rtc::CriticalSection critical_section_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(VideoAdapter);
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_BASE_VIDEOADAPTER_H_