Move occlusion info to TilePriority.

cc/resources/picture_layer_tiling.cc

Index: cc/resources/picture_layer_tiling.cc
diff --git a/cc/resources/picture_layer_tiling.cc b/cc/resources/picture_layer_tiling.cc
index 33e9038d4a2f30bff6bd3bad17bd1ece0286074a..6ad278ac4b4a89025d409e9145acb580f36b467e 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -495,7 +495,7 @@ void PictureLayerTiling::UpdateTilePriorities(
       is_occluded = occlusion_tracker->Occluded(
           render_target, tile_query_rect, draw_transform);
     }
-    tile->set_is_occluded(is_occluded);
+    tile->SetIsOccluded(tree, is_occluded);

[vmpstr, 2014/06/17 23:42:10]

I don't really like the fact that this is very brittle with respect to order.
That is, if we SetIsOccluded(tree, is_occluded) before SetPriority, then
SetPriority will wipe that flag away again.

It might be worth it to include "is_occluded" in the constructor of tile
priority. Can you do a quick check to see if that would work?

As an aside, why do we only care about visible rect occlusion? Should the loops
below have similar things or is it something that can only be in the visible
bin?

[jbedley, 2014/06/18 23:00:39]

Yes, is_occluded works in the constructor. I removed the SetIsOccluded()
function altogether, so that we just call SetPriority() once here, with either
true or false for the is_occluded bit.
I think we only care to identify occluded tiles from what's visible. If a tile
is not visible then the is_occluded bit is not applicable (although by default
it will be false).

   }
 
   // Assign soon priority to skewport tiles.