Refactor scaling.

webrtc/common_video/libyuv/webrtc_libyuv.cc

Index: webrtc/common_video/libyuv/webrtc_libyuv.cc
diff --git a/webrtc/common_video/libyuv/webrtc_libyuv.cc b/webrtc/common_video/libyuv/webrtc_libyuv.cc
index 7f5e3300c13be481b6e8a9e7793c08264f974bcf..a3febddc9a816101ea7f44af4aaf8bf8eb468b95 100644
--- a/webrtc/common_video/libyuv/webrtc_libyuv.cc
+++ b/webrtc/common_video/libyuv/webrtc_libyuv.cc
@@ -142,27 +142,28 @@ int PrintVideoFrame(const VideoFrame& frame, FILE* file) {
   return 0;
 }
 
-int ExtractBuffer(const VideoFrame& input_frame, size_t size, uint8_t* buffer) {
+int ExtractBuffer(const rtc::scoped_refptr<VideoFrameBuffer>& input_frame,
+                  size_t size,
+                  uint8_t* buffer) {
   assert(buffer);
-  if (input_frame.IsZeroSize())
+  if (!input_frame)

[pbos-webrtc, 2016/05/31 14:14:01]

Seems to me like all of these could be DCHECKs, I don't see us needing a return
code for this function

[nisse-webrtc, 2016/06/01 09:15:18]

Agree. Not fixed yet.

[nisse-webrtc, 2016/06/02 09:00:06]

Actually, return value is kind-of needed, since it's the size of the data
written.

But looking at the users of this function, it would make some sense to delete
both return value and the size argument, and leave it to the caller to know that
it writes exactly CalcBufferSize bytes. But maybe not in this cl? 

Could convert some of the checks to RTC_CHECK (callers don't recover from
failures anyway), but I'm leaving it unchanged for the moment.

     return -1;
-  size_t length =
-      CalcBufferSize(kI420, input_frame.width(), input_frame.height());
+  int width = input_frame->width();
+  int height = input_frame->height();
+  size_t length = CalcBufferSize(kI420, width, height);
   if (size < length) {
      return -1;
   }
 
-  int width = input_frame.video_frame_buffer()->width();
-  int height = input_frame.video_frame_buffer()->height();
   int chroma_width = (width + 1) / 2;
   int chroma_height = (height + 1) / 2;
 
-  libyuv::I420Copy(input_frame.video_frame_buffer()->DataY(),
-                   input_frame.video_frame_buffer()->StrideY(),
-                   input_frame.video_frame_buffer()->DataU(),
-                   input_frame.video_frame_buffer()->StrideU(),
-                   input_frame.video_frame_buffer()->DataV(),
-                   input_frame.video_frame_buffer()->StrideV(),
+  libyuv::I420Copy(input_frame->DataY(),
+                   input_frame->StrideY(),
+                   input_frame->DataU(),
+                   input_frame->StrideU(),
+                   input_frame->DataV(),
+                   input_frame->StrideV(),
                    buffer, width,
                    buffer + width*height, chroma_width,
                    buffer + width*height + chroma_width*chroma_height,
@@ -172,6 +173,9 @@ int ExtractBuffer(const VideoFrame& input_frame, size_t size, uint8_t* buffer) {
   return static_cast<int>(length);
 }
 
+int ExtractBuffer(const VideoFrame& input_frame, size_t size, uint8_t* buffer) {
+  return ExtractBuffer(input_frame.video_frame_buffer(), size, buffer);
+}
 
 int ConvertNV12ToRGB565(const uint8_t* src_frame,
                         uint8_t* dst_frame,