libvpx: Pull from upstream

source/libvpx/vpx_scale/generic/yv12extend.c

Index: source/libvpx/vpx_scale/generic/yv12extend.c
===================================================================
--- source/libvpx/vpx_scale/generic/yv12extend.c	(revision 240950)
+++ source/libvpx/vpx_scale/generic/yv12extend.c	(working copy)
@@ -84,14 +84,13 @@
 static void extend_frame(YV12_BUFFER_CONFIG *const ybf,
                          int subsampling_x, int subsampling_y,
                          int ext_size) {
-  const int c_w = (ybf->y_crop_width + subsampling_x) >> subsampling_x;
-  const int c_h = (ybf->y_crop_height + subsampling_y) >> subsampling_y;
-  const int c_et = ext_size >> subsampling_y;
-  const int c_el = ext_size >> subsampling_x;
-  const int c_eb = (ext_size + ybf->y_height - ybf->y_crop_height +
-                    subsampling_y) >> subsampling_y;
-  const int c_er = (ext_size + ybf->y_width - ybf->y_crop_width +
-                    subsampling_x) >> subsampling_x;
+  const int c_w = ybf->uv_crop_width;
+  const int c_h = ybf->uv_crop_height;
+  const int c_ext_size = ext_size >> 1;
+  const int c_et = c_ext_size;
+  const int c_el = c_ext_size;
+  const int c_eb = c_ext_size + ybf->uv_height - ybf->uv_crop_height;
+  const int c_er = c_ext_size + ybf->uv_width - ybf->uv_crop_width;
 
   assert(ybf->y_height - ybf->y_crop_height < 16);
   assert(ybf->y_width - ybf->y_crop_width < 16);