Add I420Buffer::Copy method taking plane pointers as input.

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 287624e59ec5076f72ad0d87a856a6fe8e0ba8b0..2d5949fbc4e10275b34b5f326a6d86c6c3ce4c54 100644
--- a/webrtc/common_video/include/video_frame_buffer.h
+++ b/webrtc/common_video/include/video_frame_buffer.h
@@ -58,9 +58,6 @@ class VideoFrameBuffer : public rtc::RefCountInterface {
 // Plain I420 buffer in standard memory.
 class I420Buffer : public VideoFrameBuffer {
  public:
-  I420Buffer(int width, int height);
-  I420Buffer(int width, int height, int stride_y, int stride_u, int stride_v);
-
   static rtc::scoped_refptr<I420Buffer> Create(int width, int height);
   static rtc::scoped_refptr<I420Buffer> Create(int width,
                                                int height,
@@ -68,6 +65,24 @@ class I420Buffer : public VideoFrameBuffer {
                                                int stride_u,
                                                int stride_v);
 
+  // Create a new buffer and copy the pixel data.
+  static rtc::scoped_refptr<I420Buffer> Copy(const VideoFrameBuffer& buffer);
+
+  static rtc::scoped_refptr<I420Buffer> Copy(
+      int width, int height,
+      const uint8_t* data_y, int stride_y,
+      const uint8_t* data_u, int stride_u,
+      const uint8_t* data_v, int stride_v);
+
+  // Returns a rotated versions of |src|. Native buffers are not
+  // supported. The reason this function doesn't return an I420Buffer,
+  // is that it returns |src| unchanged in case |rotation| is zero.
+  // TODO(nisse): Consider dropping the special handling of zero
+  // rotation, and leave any optimizing that case to the caller.
+  static rtc::scoped_refptr<VideoFrameBuffer> Rotate(
+      rtc::scoped_refptr<VideoFrameBuffer> src,
+      VideoRotation rotation);
+
   // Sets all three planes to all zeros. Used to work around for
   // quirks in memory checkers
   // (https://bugs.chromium.org/p/libyuv/issues/detail?id=377) and
@@ -95,9 +110,6 @@ class I420Buffer : public VideoFrameBuffer {
   void* native_handle() const override;
   rtc::scoped_refptr<VideoFrameBuffer> NativeToI420Buffer() override;
 
-  // Create a new buffer and copy the pixel data.
-  static rtc::scoped_refptr<I420Buffer> Copy(const VideoFrameBuffer& buffer);
-
   // Scale the cropped area of |src| to the size of |this| buffer, and
   // write the result into |this|.
   void CropAndScaleFrom(const VideoFrameBuffer& src,
@@ -133,14 +145,10 @@ class I420Buffer : public VideoFrameBuffer {
     ScaleFrom(*src);
   }
 
-  // Returns a rotated versions of |src|. Native buffers are not
-  // supported. The reason this function doesn't return an I420Buffer,
-  // is that it returns |src| unchanged in case |rotation| is zero.
-  static rtc::scoped_refptr<VideoFrameBuffer> Rotate(
-      rtc::scoped_refptr<VideoFrameBuffer> src,
-      VideoRotation rotation);
-
  protected:
+  I420Buffer(int width, int height);
+  I420Buffer(int width, int height, int stride_y, int stride_u, int stride_v);
+
   ~I420Buffer() override;
 
  private: