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

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 1ee97531b07aac91a9b169a08ddbba3c9b5e1477..e4a697f93e782ce858103a24cc8f782c25eef6c0 100644
--- a/webrtc/common_video/video_frame_buffer.cc
+++ b/webrtc/common_video/video_frame_buffer.cc
@@ -61,10 +61,12 @@ I420Buffer::I420Buffer(int width,
 I420Buffer::~I420Buffer() {
 }
 
+// static
 rtc::scoped_refptr<I420Buffer> I420Buffer::Create(int width, int height) {
   return new rtc::RefCountedObject<I420Buffer>(width, height);
 }
 
+// static
 rtc::scoped_refptr<I420Buffer> I420Buffer::Create(int width,
                                                   int height,
                                                   int stride_y,
@@ -128,19 +130,30 @@ rtc::scoped_refptr<VideoFrameBuffer> I420Buffer::NativeToI420Buffer() {
 
 // static
 rtc::scoped_refptr<I420Buffer> 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) {
+  // Note: May use different strides than the input data.
+  rtc::scoped_refptr<I420Buffer> buffer = Create(width, height);
+  RTC_CHECK(libyuv::I420Copy(data_y, stride_y,

[magjed_webrtc, 2016/11/28 08:39:56]

RTC_CHECK_EQ(0, ...)

[nisse-webrtc, 2016/11/28 09:44:54]

Done.

+                             data_u, stride_u,
+                             data_v, stride_v,
+                             buffer->MutableDataY(), buffer->StrideY(),
+                             buffer->MutableDataU(), buffer->StrideU(),
+                             buffer->MutableDataV(), buffer->StrideV(),
+                             width, height)
+            == 0);
+  return buffer;
+}
+
+// static
+rtc::scoped_refptr<I420Buffer> I420Buffer::Copy(
     const VideoFrameBuffer& source) {
-  int width = source.width();
-  int height = source.height();
-  rtc::scoped_refptr<I420Buffer> target = I420Buffer::Create(width, height);
-  RTC_CHECK(libyuv::I420Copy(source.DataY(), source.StrideY(),
-                             source.DataU(), source.StrideU(),
-                             source.DataV(), source.StrideV(),
-                             target->MutableDataY(), target->StrideY(),
-                             target->MutableDataU(), target->StrideU(),
-                             target->MutableDataV(), target->StrideV(),
-                             width, height) == 0);
-
-  return target;
+  return Copy(source.width(), source.height(),
+              source.DataY(), source.StrideY(),
+              source.DataU(), source.StrideU(),
+              source.DataV(), source.StrideV());
 }
 
 void I420Buffer::SetToBlack() {