VideoLayerImpl: subtract 1 from visible size when calculating tex stretch.

cc/layers/video_layer_impl.cc

Index: cc/layers/video_layer_impl.cc
diff --git a/cc/layers/video_layer_impl.cc b/cc/layers/video_layer_impl.cc
index 39b8ef20c59f072bcbc8f6815aa9d66ea8a82edb..fe9e85c7aab177f68d7202d2dbfa76f16ad7839b 100644
--- a/cc/layers/video_layer_impl.cc
+++ b/cc/layers/video_layer_impl.cc
@@ -184,7 +184,12 @@ void VideoLayerImpl::AppendQuads(RenderPass* render_pass,
   if (visible_quad_rect.IsEmpty())
     return;
 
-  // Pixels for macroblocked formats.
+  // Pixels for macroblocked formats. To prevent sampling outside the visible
+  // rect, stretch the video if needed.
+  if (visible_rect.width() < coded_size.width() && visible_rect.width() > 1)
+    visible_rect.set_width(visible_rect.width() - 1);
+  if (visible_rect.height() < coded_size.height() && visible_rect.height() > 1)
+    visible_rect.set_height(visible_rect.height() - 1);
   const float tex_width_scale =
       static_cast<float>(visible_rect.width()) / coded_size.width();
   const float tex_height_scale =