Consider occluded tiles during eviction with occluded as Tile property.

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 baddcf13cee9627225c7ae47853729930f080b8e..5cb9cf88a3e46649b724389b18f9384ed3b5e0dd 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -35,11 +35,41 @@ class TileEvictionOrder {
     const TilePriority& b_priority =
         b->priority_for_tree_priority(tree_priority_);
 
-    if (a_priority.priority_bin == b_priority.priority_bin &&
-        a->required_for_activation() != b->required_for_activation()) {
+    // Evict a before b if their priority bins differ and a has the higher
+    // priority bin.
+    if (a_priority.priority_bin != b_priority.priority_bin)
+      return a_priority.priority_bin > b_priority.priority_bin;
+
+    // Or if a is not required and b is required.
+    if (a->required_for_activation() != b->required_for_activation())
       return b->required_for_activation();
+
+    // Or if a is occluded and b is unoccluded.
+    bool a_is_occluded;

[danakj, 2014/07/09 17:38:40]

initialize these to false

+    bool b_is_occluded;
+
+    switch (tree_priority_) {

[vmpstr, 2014/07/09 23:23:06]

Maybe it's worth having something like is_occluded_for_tree_priority simimlar to
priority_for_tree_priority?

[jbedley, 2014/07/11 00:19:38]

Done.

+      case SMOOTHNESS_TAKES_PRIORITY:
+        a_is_occluded = a->is_occluded(ACTIVE_TREE);
+        b_is_occluded = b->is_occluded(ACTIVE_TREE);
+        break;
+      case NEW_CONTENT_TAKES_PRIORITY:
+        a_is_occluded = a->is_occluded(PENDING_TREE);
+        b_is_occluded = b->is_occluded(PENDING_TREE);
+        break;
+      case SAME_PRIORITY_FOR_BOTH_TREES:
+        a_is_occluded =
+            a->is_occluded(ACTIVE_TREE) && a->is_occluded(PENDING_TREE);
+        b_is_occluded =
+            b->is_occluded(ACTIVE_TREE) && a->is_occluded(PENDING_TREE);
+        break;
     }
-    return b_priority.IsHigherPriorityThan(a_priority);
+
+    if (a_is_occluded != b_is_occluded)
+      return a_is_occluded;
+
+    // Or if a is farther away from visible.
+    return a_priority.distance_to_visible > b_priority.distance_to_visible;
   }
 
  private: