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 d173cc6c2b6d0f511a802fb95d167aed98f9a1d1..e893c5fab2654f54b9f482f100a292ab7e278ae7 100644
--- a/cc/layers/video_layer_impl.cc
+++ b/cc/layers/video_layer_impl.cc
@@ -185,10 +185,15 @@ void VideoLayerImpl::AppendQuads(RenderPass* render_pass,
     return;
 
   // Pixels for macroblocked formats.
-  const float tex_width_scale =
-      static_cast<float>(visible_rect.width()) / coded_size.width();
-  const float tex_height_scale =
-      static_cast<float>(visible_rect.height()) / coded_size.height();
+  float visible_width = static_cast<float>(visible_rect.width());

[enne (OOO), 2016/02/01 21:00:03]

Please leave these as ints and put the static cast down on tex_width_scale.

[wuchengli, 2016/02/02 05:37:27]

Done.

+  float visible_height = static_cast<float>(visible_rect.height());
+  // To prevent sampling outside the visible rect, stretch the video if needed.
+  if (visible_rect.width() < coded_size.width() && visible_rect.width() > 1)
+    visible_width -= 1.f;

[wuchengli, 2016/02/01 03:29:51]

Do we want this for RGB_RESOURCE only or for all frame resource type?

[enne (OOO), 2016/02/01 21:00:03]

If you do this here, it will be for all formats but YUV (just because of how the
code works).  You might want to fix that as well?

If it's the case that textures outside of the visible rect are garbage, then it
probably should be scaled for all formats in this case.

[wuchengli, 2016/02/02 05:37:27]

Done.

+  if (visible_rect.height() < coded_size.height() && visible_rect.height() > 1)
+    visible_height -= 1.f;
+  const float tex_width_scale = visible_width / coded_size.width();
+  const float tex_height_scale = visible_height / coded_size.height();
 
   switch (frame_resource_type_) {
     // TODO(danakj): Remove this, hide it in the hardware path.