Refactor scaling.

webrtc/common_video/include/video_frame_buffer.h

Index: webrtc/common_video/include/video_frame_buffer.h
diff --git a/webrtc/common_video/include/video_frame_buffer.h b/webrtc/common_video/include/video_frame_buffer.h
index 890922f21be2dfa9896db25b5627ebc8be0b0c53..dc51164450ce6bc35d1cbbf0fcf737276123e2e8 100644
--- a/webrtc/common_video/include/video_frame_buffer.h
+++ b/webrtc/common_video/include/video_frame_buffer.h
@@ -119,6 +119,21 @@ class I420Buffer : public VideoFrameBuffer {
   static rtc::scoped_refptr<I420Buffer> Copy(
       const rtc::scoped_refptr<VideoFrameBuffer>& buffer);
 
+  // Scale the cropped area of |src| to the size of |this| buffer, and
+  // write the result into |this|.
+  void CropAndScaleFrom(const rtc::scoped_refptr<VideoFrameBuffer>& src,
+                        int offset_x,
+                        int offset_y,
+                        int crop_width,
+                        int crop_height);
+
+  // The common case of a center crop, when needed to adjust the
+  // aspect ratio without distorting the image.
+  void CropAndScaleFrom(const rtc::scoped_refptr<VideoFrameBuffer>& src);
+
+  // Scale all of |src| to the size of |this| buffer, with no cropping.
+  void ScaleFrom(const rtc::scoped_refptr<VideoFrameBuffer>& src);
+
  protected:
   ~I420Buffer() override;
 
@@ -196,13 +211,6 @@ class WrappedI420Buffer : public webrtc::VideoFrameBuffer {
   rtc::Callback0<void> no_longer_used_cb_;
 };
 
-// Helper function to crop |buffer| without making a deep copy. May only be used
-// for non-native frames.
-rtc::scoped_refptr<VideoFrameBuffer> ShallowCenterCrop(
-    const rtc::scoped_refptr<VideoFrameBuffer>& buffer,
-    int cropped_width,
-    int cropped_height);
-
 }  // namespace webrtc
 
 #endif  // WEBRTC_COMMON_VIDEO_INCLUDE_VIDEO_FRAME_BUFFER_H_