cc: Do not ignore layers without valid priorities during eviction.

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index c3c7ca021104ba5f2468b233838d45beee16c845..8382ea6e4138118a4138f6c7baf5d88c0b67117b 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -688,6 +688,12 @@ PictureLayerTiling* PictureLayerImpl::GetRecycledTwinTiling(
   return recycled_twin->tilings_->TilingAtScale(tiling->contents_scale());
 }
 
+TilePriority::PriorityBin PictureLayerImpl::GetMaxTilePriorityBin() const {
+  if (!HasValidTilePriorities())
+    return TilePriority::EVENTUALLY;
+  return TilePriority::NOW;
+}
+
 size_t PictureLayerImpl::GetMaxTilesForInterestArea() const {
   return layer_tree_impl()->settings().max_tiles_for_interest_area;
 }