cc: Start using raster/eviction iterators in tile manager

cc/resources/picture_layer_tiling.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/resources/picture_layer_tiling.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 
@@ skipping 820 matching lines @@
   }
 
   current_tile_ =
       tiling_->TileAt(visible_iterator_.index_x(), visible_iterator_.index_y());
   if (!current_tile_ || !TileNeedsRaster(current_tile_))
     ++(*this);
 }
 
 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);
 
   do {
     type_ = static_cast<TilePriority::PriorityBin>(type_ + 1);
     if (type_ == TilePriority::EVENTUALLY) {
       spiral_iterator_ = TilingData::SpiralDifferenceIterator(
           &tiling_->tiling_data_,
           eventually_rect_in_content_space_,
           skewport_in_content_space_,
@@ skipping 104 matching lines @@
   tiling_->UpdateEvictionCacheIfNeeded(tree_priority_);
   tile_iterator_ = tiling_->eviction_tiles_cache_.begin();
   is_valid_ = true;
   if (tile_iterator_ != tiling_->eviction_tiles_cache_.end() &&
       !(*tile_iterator_)->HasResources()) {
     ++(*this);
   }
 }
 
 }  // namespace cc