New static I420Buffer::Rotate method, to replace GetCopyWithRotationApplied.

webrtc/common_video/video_frame_buffer.cc

Index: webrtc/common_video/video_frame_buffer.cc
diff --git a/webrtc/common_video/video_frame_buffer.cc b/webrtc/common_video/video_frame_buffer.cc
index fd20e564f5e5bf855a331393d4f443975f3e8867..ae0de4322284be31db6e9352137a1af42015fade 100644
--- a/webrtc/common_video/video_frame_buffer.cc
+++ b/webrtc/common_video/video_frame_buffer.cc
@@ -46,6 +46,42 @@ uint8_t* VideoFrameBuffer::MutableDataV() {
 
 VideoFrameBuffer::~VideoFrameBuffer() {}
 
+// static
+rtc::scoped_refptr<VideoFrameBuffer> VideoFrameBuffer::Rotate(
+    const rtc::scoped_refptr<VideoFrameBuffer>& src,
+    VideoRotation rotation) {
+  if (rotation == webrtc::kVideoRotation_0) {
+    return src;
+  }
+
+  int current_width = src->width();

[magjed_webrtc, 2016/08/26 12:04:15]

I would prefer if you removed current_width and use src->width() directly.

[nisse-webrtc, 2016/08/26 12:31:40]

Done.

+  int current_height = src->height();
+
+  int rotated_width = current_width;
+  int rotated_height = current_height;
+  if (rotation == webrtc::kVideoRotation_90 ||
+      rotation == webrtc::kVideoRotation_270) {
+    std::swap(rotated_width, rotated_height);
+  }
+
+  rtc::scoped_refptr<webrtc::I420Buffer> buffer =
+      I420Buffer::Create(rotated_width, rotated_height);
+
+  // TODO(guoweis): Add a function in webrtc_libyuv.cc to convert from

[magjed_webrtc, 2016/08/26 12:04:15]

Remove this TODO. I think guoweis has moved on from working with this. Static
cast works for me.

[nisse-webrtc, 2016/08/26 12:31:40]

Done.

+  // VideoRotation to libyuv::RotationMode.
+  int res = libyuv::I420Rotate(
+      src->DataY(), src->StrideY(),
+      src->DataU(), src->StrideU(),
+      src->DataV(), src->StrideV(),
+      buffer->MutableDataY(), buffer->StrideY(), buffer->MutableDataU(),
+      buffer->StrideU(), buffer->MutableDataV(), buffer->StrideV(),
+      current_width, current_height,
+      static_cast<libyuv::RotationMode>(rotation));
+  RTC_DCHECK_EQ(res, 0);
+
+  return buffer;
+}
+
 I420Buffer::I420Buffer(int width, int height)
     : I420Buffer(width, height, width, (width + 1) / 2, (width + 1) / 2) {
 }