Move occlusion info to TilePriority.

cc/resources/tile_priority.h

Index: cc/resources/tile_priority.h
diff --git a/cc/resources/tile_priority.h b/cc/resources/tile_priority.h
index f8ac9c6c7b0e7a148e929b10a6ab8fbe0392cd24..318885fbe5209ba9d57b9bfca89dec0af5353549 100644
--- a/cc/resources/tile_priority.h
+++ b/cc/resources/tile_priority.h
@@ -46,6 +46,7 @@ struct CC_EXPORT TilePriority {
   TilePriority()
       : resolution(NON_IDEAL_RESOLUTION),
         required_for_activation(false),
+        is_occluded(false),
         priority_bin(EVENTUALLY),
         distance_to_visible(std::numeric_limits<float>::infinity()) {}
 
@@ -54,6 +55,7 @@ struct CC_EXPORT TilePriority {
                float distance_to_visible)
       : resolution(resolution),
         required_for_activation(false),
+        is_occluded(false),
         priority_bin(bin),
         distance_to_visible(distance_to_visible) {}
 
@@ -70,6 +72,8 @@ struct CC_EXPORT TilePriority {
     required_for_activation =
         active.required_for_activation || pending.required_for_activation;
 
+    is_occluded = active.is_occluded && pending.is_occluded;
+
     if (active.priority_bin < pending.priority_bin) {
       priority_bin = active.priority_bin;
       distance_to_visible = active.distance_to_visible;
@@ -89,7 +93,8 @@ struct CC_EXPORT TilePriority {
     return resolution == other.resolution &&
            priority_bin == other.priority_bin &&
            distance_to_visible == other.distance_to_visible &&
-           required_for_activation == other.required_for_activation;
+           required_for_activation == other.required_for_activation &&
+           is_occluded == other.is_occluded;
   }
 
   bool operator !=(const TilePriority& other) const {
@@ -104,6 +109,7 @@ struct CC_EXPORT TilePriority {
 
   TileResolution resolution;
   bool required_for_activation;
+  bool is_occluded;
   PriorityBin priority_bin;
   float distance_to_visible;
 };