cc: Start using raster/eviction iterators in tile manager

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 f0b38db18a857bb8c3009da185df33bd43ec2e98..a220bcfc79b55b7357ada21e98ed7f56a90dc98f 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -838,6 +838,21 @@ PictureLayerTiling::TilingRasterTileIterator::TilingRasterTileIterator(
 
 PictureLayerTiling::TilingRasterTileIterator::~TilingRasterTileIterator() {}
 
+bool
+PictureLayerTiling::TilingRasterTileIterator::HasTilesRequiredForActivation()
+    const {
+  if (!*this || get_type() != TilePriority::NOW)
+    return false;
+
+  for (TilingData::Iterator it = visible_iterator_; it; ++it) {
+    std::pair<int, int> next_index = visible_iterator_.index();
+    Tile* tile = tiling_->TileAt(next_index.first, next_index.second);
+    if (tile && tile->required_for_activation())
+      return true;
+  }
+  return false;
+}
+
 void PictureLayerTiling::TilingRasterTileIterator::AdvancePhase() {
   DCHECK_LT(type_, TilePriority::EVENTUALLY);