cleanup: Use NV12Scale from libyuv

NV12Scale has been recently added to libyuv, so there is no reason
to use a self-written version.

Change-Id: I6b207788e964c7ee21697eab9931fa2854031718
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2580916Reviewed-by: Thomas Guilbert <tguilbert@chromium.org>
Reviewed-by: Matthew Wolenetz <wolenetz@chromium.org>
Commit-Queue: Eugene Zemtsov <eugene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835582}

media/gpu/chromeos/libyuv_image_processor_backend.cc

@@ -19,60 +19,6 @@ namespace media {
 
 namespace {
 
-// TODO(https://bugs.chromium.org/p/libyuv/issues/detail?id=838): Remove
-// this once libyuv implements NV12Scale and use the libyuv::NV12Scale().
-// This is copy-pasted from
-// third_party/webrtc/common_video/libyuv/include/webrtc_libyuv.h.
-void NV12Scale(uint8_t* tmp_buffer,
-               const uint8_t* src_y,
-               int src_stride_y,
-               const uint8_t* src_uv,
-               int src_stride_uv,
-               int src_width,
-               int src_height,
-               uint8_t* dst_y,
-               int dst_stride_y,
-               uint8_t* dst_uv,
-               int dst_stride_uv,
-               int dst_width,
-               int dst_height) {
-  const int src_chroma_width = (src_width + 1) / 2;
-  const int src_chroma_height = (src_height + 1) / 2;
-
-  if (src_width == dst_width && src_height == dst_height) {
-    // No scaling.
-    libyuv::CopyPlane(src_y, src_stride_y, dst_y, dst_stride_y, src_width,
-                      src_height);
-    libyuv::CopyPlane(src_uv, src_stride_uv, dst_uv, dst_stride_uv,
-                      src_chroma_width * 2, src_chroma_height);
-    return;
-  }
-
-  // Scaling.
-  // Allocate temporary memory for spitting UV planes and scaling them.
-  const int dst_chroma_width = (dst_width + 1) / 2;
-  const int dst_chroma_height = (dst_height + 1) / 2;
-
-  uint8_t* const src_u = tmp_buffer;
-  uint8_t* const src_v = src_u + src_chroma_width * src_chroma_height;
-  uint8_t* const dst_u = src_v + src_chroma_width * src_chroma_height;
-  uint8_t* const dst_v = dst_u + dst_chroma_width * dst_chroma_height;
-
-  // Split source UV plane into separate U and V plane using the temporary data.
-  libyuv::SplitUVPlane(src_uv, src_stride_uv, src_u, src_chroma_width, src_v,
-                       src_chroma_width, src_chroma_width, src_chroma_height);
-
-  // Scale the planes.
-  libyuv::I420Scale(
-      src_y, src_stride_y, src_u, src_chroma_width, src_v, src_chroma_width,
-      src_width, src_height, dst_y, dst_stride_y, dst_u, dst_chroma_width,
-      dst_v, dst_chroma_width, dst_width, dst_height, libyuv::kFilterBox);
-
-  // Merge the UV planes into the destination.
-  libyuv::MergeUVPlane(dst_u, dst_chroma_width, dst_v, dst_chroma_width, dst_uv,
-                       dst_stride_uv, dst_chroma_width, dst_chroma_height);
-}
-
 // TODO(https://bugs.chromium.org/p/libyuv/issues/detail?id=840): Remove
 // this once libyuv implements NV12Rotate() and use the libyuv::NV12Rotate().
 bool NV12Rotate(uint8_t* tmp_buffer,
@@ -254,19 +200,6 @@ std::unique_ptr<ImageProcessorBackend> LibYUVImageProcessorBackend::Create(
                << output_config.visible_rect.ToString();
       return nullptr;
     }
-    // Down-scaling support only.
-    // This restriction is to simplify |intermediate_frame_| creation. It is
-    // used as |tmp_buffer| in NV12Scale().
-    // TODO(hiroh): Remove this restriction once libyuv:NV12Scale() is arrived.
-    if (!gfx::Rect(input_config.visible_rect.size())
-             .Contains(gfx::Rect(output_config.visible_rect.size())) &&
-        relative_rotation == VIDEO_ROTATION_0) {
-      VLOGF(2) << "Down-scaling support only, input_config.visible_rect="
-               << input_config.visible_rect.ToString()
-               << ", output_config.visible_rect="
-               << output_config.visible_rect.ToString();
-      return nullptr;
-    }
   }
 
   scoped_refptr<VideoFrame> intermediate_frame;
@@ -429,19 +362,14 @@ int LibYUVImageProcessorBackend::DoConversion(const VideoFrame* const input,
         }
 
         // Scaling mode.
-        // The size of |tmp_buffer| of NV12Scale() should be
-        // input_visible_rect().GetArea() / 2 +
-        // output_visible_rect().GetArea() / 2. Although |intermediate_frame_|
-        // is much larger than the required size, we use the frame to simplify
-        // the code.
-        NV12Scale(intermediate_frame_->data(0),
-                  input->visible_data(VideoFrame::kYPlane),
-                  input->stride(VideoFrame::kYPlane),
-                  input->visible_data(VideoFrame::kUPlane),
-                  input->stride(VideoFrame::kUPlane),
-                  input->visible_rect().width(), input->visible_rect().height(),
-                  Y_UV_DATA(output), output->visible_rect().width(),
-                  output->visible_rect().height());
+        libyuv::NV12Scale(input->visible_data(VideoFrame::kYPlane),
+                          input->stride(VideoFrame::kYPlane),
+                          input->visible_data(VideoFrame::kUPlane),
+                          input->stride(VideoFrame::kUPlane),
+                          input->visible_rect().width(),
+                          input->visible_rect().height(), Y_UV_DATA(output),
+                          output->visible_rect().width(),
+                          output->visible_rect().height(), libyuv::kFilterBox);
         return 0;
       default:
         VLOGF(1) << "Unexpected input format: " << input->format();