Rotation into Video Layer + Content Transform

cc/layers/video_layer.cc

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/video_layer.h"
 
 #include "cc/layers/video_layer_impl.h"
 
 namespace cc {
 
@@ skipping 18 matching lines @@
   // Video layer doesn't update any resources from the main thread side,
   // but repaint rects need to be sent to the VideoLayerImpl via commit.
   //
   // This is the inefficient legacy redraw path for videos.  It's better to
   // communicate this directly to the VideoLayerImpl.
   updated |= !update_rect_.IsEmpty();
 
   return updated;
 }
 
+void VideoLayer::PushPropertiesTo(LayerImpl* impl) {
+  Layer::PushPropertiesTo(impl);
+  gfx::Transform transform = impl->transform();
+  bool transform_is_invertible = impl->transform_is_invertible();
+  gfx::Size content_bounds = impl->content_bounds();
+
+  switch (video_rotation_) {
+    case media::VIDEO_ROTATION_90:
+      transform.Rotate(90.0);
+      transform.Translate(0.0, -content_bounds.width());
+      content_bounds =

[enne (OOO), 2014/07/23 21:46:52]

I think content bounds shouldn't be modified here.  The bounds of the video are
still the same.  It is just rotated when drawn.

[suderman, 2014/07/23 23:27:01]

The content bounds are used to construct the video layer impl's quad_rect. This
quad rect must have the dimensions unrotated. As blink is given the rotated size
to layout the page the content bounds may not reflect the unrotated size and
need to be swapped.

[enne (OOO), 2014/07/23 23:39:26]

Thanks! That was not obvious at all to me.

So, Blink doesn't know the video is rotated per se but does know the rotated
bounds?

I think you also need to update bounds() as well as content_bounds() if you're
going to do this.  Can you also leave a comment about why this has to happen?

+          gfx::Size(content_bounds.height(), content_bounds.width());
+      break;
+    case media::VIDEO_ROTATION_180:
+      transform.Rotate(180.0);
+      transform.Translate(-content_bounds.width(), -content_bounds.height());
+      break;
+    case media::VIDEO_ROTATION_270:
+      transform.Rotate(270.0);
+      transform.Translate(-content_bounds.height(), 0);
+      content_bounds =
+          gfx::Size(content_bounds.height(), content_bounds.width());
+    case media::VIDEO_ROTATION_0:
+      break;
+  }
+
+  impl->draw_properties().content_bounds = content_bounds;
+  impl->SetTransformAndInvertibility(transform, transform_is_invertible);
+}
+
 }  // namespace cc