Revert of cc: Remove tile sharing from tilings.

cc/resources/tiling_set_eviction_queue.cc

Index: cc/resources/tiling_set_eviction_queue.cc
diff --git a/cc/resources/tiling_set_eviction_queue.cc b/cc/resources/tiling_set_eviction_queue.cc
index bbe689d2617e9c79b69d622c9a3ee6c23f3f1bb5..43d085b629f7047e09ce1d8b22748115b0df8ccf 100644
--- a/cc/resources/tiling_set_eviction_queue.cc
+++ b/cc/resources/tiling_set_eviction_queue.cc
@@ -7,6 +7,33 @@
 #include "cc/resources/tiling_set_eviction_queue.h"
 
 namespace cc {
+namespace {
+
+bool IsSharedOutOfOrderTile(WhichTree tree, const Tile* tile) {
+  if (!tile->is_shared())
+    return false;
+
+  // The priority for tile priority of a shared tile will be a combined
+  // priority thus return shared tiles from a higher priority tree as
+  // it is out of order for a lower priority tree.
+  WhichTree twin_tree = tree == ACTIVE_TREE ? PENDING_TREE : ACTIVE_TREE;
+  const TilePriority& priority = tile->priority(tree);
+  const TilePriority& twin_priority = tile->priority(twin_tree);
+  if (priority.priority_bin != twin_priority.priority_bin)
+    return priority.priority_bin > twin_priority.priority_bin;
+  const bool occluded = tile->is_occluded(tree);
+  const bool twin_occluded = tile->is_occluded(twin_tree);
+  if (occluded != twin_occluded)
+    return occluded;
+  if (priority.distance_to_visible != twin_priority.distance_to_visible)
+    return priority.distance_to_visible > twin_priority.distance_to_visible;
+
+  // If priorities are the same, it does not matter which tree returns
+  // the tile. Let's pick the pending tree.
+  return tree != PENDING_TREE;
+}
+
+}  // namespace
 
 TilingSetEvictionQueue::TilingSetEvictionQueue(
     PictureLayerTilingSet* tiling_set,
@@ -36,43 +63,28 @@
   tilings_.reserve(tiling_set->num_tilings());
   // Generate all of the tilings in the order described in the header comment
   // for this class.
-  PictureLayerTilingSet::TilingRange range =
+  auto range =
       tiling_set->GetTilingRange(PictureLayerTilingSet::HIGHER_THAN_HIGH_RES);
-  for (int i = range.start; i < range.end; ++i) {
-    PictureLayerTiling* tiling = tiling_set->tiling_at(i);
-    if (tiling->has_tiles())
-      tilings_.push_back(tiling);
-  }
+  for (int i = range.start; i < range.end; ++i)
+    tilings_.push_back(tiling_set->tiling_at(i));
 
   range = tiling_set->GetTilingRange(PictureLayerTilingSet::LOWER_THAN_LOW_RES);
-  for (int i = range.end - 1; i >= range.start; --i) {
-    PictureLayerTiling* tiling = tiling_set->tiling_at(i);
-    if (tiling->has_tiles())
-      tilings_.push_back(tiling);
-  }
+  for (int i = range.end - 1; i >= range.start; --i)
+    tilings_.push_back(tiling_set->tiling_at(i));
 
   range = tiling_set->GetTilingRange(
       PictureLayerTilingSet::BETWEEN_HIGH_AND_LOW_RES);
-  for (int i = range.end - 1; i >= range.start; --i) {
-    PictureLayerTiling* tiling = tiling_set->tiling_at(i);
-    if (tiling->has_tiles())
-      tilings_.push_back(tiling);
-  }
+  for (int i = range.end - 1; i >= range.start; --i)
+    tilings_.push_back(tiling_set->tiling_at(i));
 
   range = tiling_set->GetTilingRange(PictureLayerTilingSet::LOW_RES);
-  for (int i = range.start; i < range.end; ++i) {
-    PictureLayerTiling* tiling = tiling_set->tiling_at(i);
-    if (tiling->has_tiles())
-      tilings_.push_back(tiling);
-  }
+  for (int i = range.start; i < range.end; ++i)
+    tilings_.push_back(tiling_set->tiling_at(i));
 
   range = tiling_set->GetTilingRange(PictureLayerTilingSet::HIGH_RES);
-  for (int i = range.start; i < range.end; ++i) {
-    PictureLayerTiling* tiling = tiling_set->tiling_at(i);
-    if (tiling->has_tiles())
-      tilings_.push_back(tiling);
-  }
-  DCHECK_GE(tiling_set->num_tilings(), tilings_.size());
+  for (int i = range.start; i < range.end; ++i)
+    tilings_.push_back(tiling_set->tiling_at(i));
+  DCHECK_EQ(tiling_set->num_tilings(), tilings_.size());
 }
 
 void TilingSetEvictionQueue::AdvancePhase() {
@@ -95,20 +107,6 @@
             &tilings_, tree_, skip_shared_out_of_order_tiles_);
         if (!skewport_iterator_.done())
           current_tile_ = *skewport_iterator_;
-        break;
-      case PENDING_VISIBLE_RECT:
-        pending_visible_iterator_ = PendingVisibleTilingIterator(
-            &tilings_, tree_, skip_shared_out_of_order_tiles_,
-            false /* return required for activation tiles */);
-        if (!pending_visible_iterator_.done())
-          current_tile_ = *pending_visible_iterator_;
-        break;
-      case PENDING_VISIBLE_RECT_REQUIRED_FOR_ACTIVATION:
-        pending_visible_iterator_ = PendingVisibleTilingIterator(
-            &tilings_, tree_, skip_shared_out_of_order_tiles_,
-            true /* return required for activation tiles */);
-        if (!pending_visible_iterator_.done())
-          current_tile_ = *pending_visible_iterator_;
         break;
       case VISIBLE_RECT_OCCLUDED:
         visible_iterator_ = VisibleTilingIterator(
@@ -179,12 +177,6 @@
       if (!skewport_iterator_.done())
         current_tile_ = *skewport_iterator_;
       break;
-    case PENDING_VISIBLE_RECT:
-    case PENDING_VISIBLE_RECT_REQUIRED_FOR_ACTIVATION:
-      ++pending_visible_iterator_;
-      if (!pending_visible_iterator_.done())
-        current_tile_ = *pending_visible_iterator_;
-      break;
     case VISIBLE_RECT_OCCLUDED:
     case VISIBLE_RECT_UNOCCLUDED:
     case VISIBLE_RECT_REQUIRED_FOR_ACTIVATION_OCCLUDED:
@@ -210,13 +202,11 @@
 TilingSetEvictionQueue::EvictionRectIterator::EvictionRectIterator(
     std::vector<PictureLayerTiling*>* tilings,
     WhichTree tree,
-    bool skip_shared_out_of_order_tiles,
-    bool skip_pending_visible_rect)
+    bool skip_shared_out_of_order_tiles)
     : tile_(nullptr),
       tilings_(tilings),
       tree_(tree),
       skip_shared_out_of_order_tiles_(skip_shared_out_of_order_tiles),
-      skip_pending_visible_rect_(skip_pending_visible_rect),
       tiling_index_(0) {
 }
 
@@ -238,16 +228,15 @@
 template <typename TilingIteratorType>
 bool TilingSetEvictionQueue::EvictionRectIterator::GetFirstTileAndCheckIfValid(
     TilingIteratorType* iterator) {
-  PictureLayerTiling* tiling = (*tilings_)[tiling_index_];
-  tile_ = tiling->TileAt(iterator->index_x(), iterator->index_y());
+  tile_ = (*tilings_)[tiling_index_]->TileAt(iterator->index_x(),
+                                             iterator->index_y());
   // If there's nothing to evict, return false.
   if (!tile_ || !tile_->HasResource())
     return false;
-  if (skip_pending_visible_rect_ &&
-      tiling->pending_visible_rect().Intersects(tile_->content_rect())) {
+  (*tilings_)[tiling_index_]->UpdateTileAndTwinPriority(tile_);
+  // If the tile is out of order, return false.
+  if (skip_shared_out_of_order_tiles_ && IsSharedOutOfOrderTile(tree_, tile_))
     return false;
-  }
-  (*tilings_)[tiling_index_]->UpdateTileAndTwinPriority(tile_);
   // In other cases, the tile we got is a viable candidate, return true.
   return true;
 }
@@ -257,21 +246,18 @@
     std::vector<PictureLayerTiling*>* tilings,
     WhichTree tree,
     bool skip_shared_out_of_order_tiles)
-    : EvictionRectIterator(tilings,
-                           tree,
-                           skip_shared_out_of_order_tiles,
-                           true /* skip_pending_visible_rect */) {
+    : EvictionRectIterator(tilings, tree, skip_shared_out_of_order_tiles) {
   // Find the first tiling with a tile.
   while (tiling_index_ < tilings_->size()) {
-    if (!(*tilings_)[tiling_index_]->has_eventually_rect_tiles()) {
-      ++tiling_index_;
-      continue;
-    }
-    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_eventually_rect(),
-        (*tilings_)[tiling_index_]->current_skewport_rect(),
-        (*tilings_)[tiling_index_]->current_soon_border_rect());
+    if (!((*tilings_))[tiling_index_]->has_eventually_rect_tiles()) {
+      ++tiling_index_;
+      continue;
+    }
+    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_eventually_rect(),
+        ((*tilings_))[tiling_index_]->current_skewport_rect(),
+        ((*tilings_))[tiling_index_]->current_soon_border_rect());
     if (!iterator_) {
       ++tiling_index_;
       continue;
@@ -290,13 +276,13 @@
   bool found_tile = AdvanceToNextTile(&iterator_);
   while (!found_tile && (tiling_index_ + 1) < tilings_->size()) {
     ++tiling_index_;
-    if (!(*tilings_)[tiling_index_]->has_eventually_rect_tiles())
-      continue;
-    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_eventually_rect(),
-        (*tilings_)[tiling_index_]->current_skewport_rect(),
-        (*tilings_)[tiling_index_]->current_soon_border_rect());
+    if (!((*tilings_))[tiling_index_]->has_eventually_rect_tiles())
+      continue;
+    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_eventually_rect(),
+        ((*tilings_))[tiling_index_]->current_skewport_rect(),
+        ((*tilings_))[tiling_index_]->current_soon_border_rect());
     if (!iterator_)
       continue;
     found_tile = GetFirstTileAndCheckIfValid(&iterator_);
@@ -311,21 +297,18 @@
     std::vector<PictureLayerTiling*>* tilings,
     WhichTree tree,
     bool skip_shared_out_of_order_tiles)
-    : EvictionRectIterator(tilings,
-                           tree,
-                           skip_shared_out_of_order_tiles,
-                           true /* skip_pending_visible_rect */) {
+    : EvictionRectIterator(tilings, tree, skip_shared_out_of_order_tiles) {
   // Find the first tiling with a tile.
   while (tiling_index_ < tilings_->size()) {
-    if (!(*tilings_)[tiling_index_]->has_soon_border_rect_tiles()) {
-      ++tiling_index_;
-      continue;
-    }
-    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_soon_border_rect(),
-        (*tilings_)[tiling_index_]->current_skewport_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect());
+    if (!((*tilings_))[tiling_index_]->has_soon_border_rect_tiles()) {
+      ++tiling_index_;
+      continue;
+    }
+    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_soon_border_rect(),
+        ((*tilings_))[tiling_index_]->current_skewport_rect(),
+        ((*tilings_))[tiling_index_]->current_visible_rect());
     if (!iterator_) {
       ++tiling_index_;
       continue;
@@ -344,13 +327,13 @@
   bool found_tile = AdvanceToNextTile(&iterator_);
   while (!found_tile && (tiling_index_ + 1) < tilings_->size()) {
     ++tiling_index_;
-    if (!(*tilings_)[tiling_index_]->has_soon_border_rect_tiles())
-      continue;
-    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_soon_border_rect(),
-        (*tilings_)[tiling_index_]->current_skewport_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect());
+    if (!((*tilings_))[tiling_index_]->has_soon_border_rect_tiles())
+      continue;
+    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_soon_border_rect(),
+        ((*tilings_))[tiling_index_]->current_skewport_rect(),
+        ((*tilings_))[tiling_index_]->current_visible_rect());
     if (!iterator_)
       continue;
     found_tile = GetFirstTileAndCheckIfValid(&iterator_);
@@ -365,21 +348,18 @@
     std::vector<PictureLayerTiling*>* tilings,
     WhichTree tree,
     bool skip_shared_out_of_order_tiles)
-    : EvictionRectIterator(tilings,
-                           tree,
-                           skip_shared_out_of_order_tiles,
-                           true /* skip_pending_visible_rect */) {
+    : EvictionRectIterator(tilings, tree, skip_shared_out_of_order_tiles) {
   // Find the first tiling with a tile.
   while (tiling_index_ < tilings_->size()) {
-    if (!(*tilings_)[tiling_index_]->has_skewport_rect_tiles()) {
-      ++tiling_index_;
-      continue;
-    }
-    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_skewport_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect());
+    if (!((*tilings_))[tiling_index_]->has_skewport_rect_tiles()) {
+      ++tiling_index_;
+      continue;
+    }
+    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_skewport_rect(),
+        ((*tilings_))[tiling_index_]->current_visible_rect(),
+        ((*tilings_))[tiling_index_]->current_visible_rect());
     if (!iterator_) {
       ++tiling_index_;
       continue;
@@ -398,13 +378,13 @@
   bool found_tile = AdvanceToNextTile(&iterator_);
   while (!found_tile && (tiling_index_ + 1) < tilings_->size()) {
     ++tiling_index_;
-    if (!(*tilings_)[tiling_index_]->has_skewport_rect_tiles())
-      continue;
-    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_skewport_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect());
+    if (!((*tilings_))[tiling_index_]->has_skewport_rect_tiles())
+      continue;
+    iterator_ = TilingData::ReverseSpiralDifferenceIterator(
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_skewport_rect(),
+        ((*tilings_))[tiling_index_]->current_visible_rect(),
+        ((*tilings_))[tiling_index_]->current_visible_rect());
     if (!iterator_)
       continue;
     found_tile = GetFirstTileAndCheckIfValid(&iterator_);
@@ -412,73 +392,6 @@
       found_tile = AdvanceToNextTile(&iterator_);
   }
   return *this;
-}
-
-// PendingVisibleIterator
-TilingSetEvictionQueue::PendingVisibleTilingIterator::
-    PendingVisibleTilingIterator(std::vector<PictureLayerTiling*>* tilings,
-                                 WhichTree tree,
-                                 bool skip_shared_out_of_order_tiles,
-                                 bool return_required_for_activation_tiles)
-    : EvictionRectIterator(tilings,
-                           tree,
-                           skip_shared_out_of_order_tiles,
-                           false /* skip_pending_visible_rect */),
-      return_required_for_activation_tiles_(
-          return_required_for_activation_tiles) {
-  // Find the first tiling with a tile.
-  while (tiling_index_ < tilings_->size()) {
-    iterator_ = TilingData::DifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->pending_visible_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect());
-    if (!iterator_) {
-      ++tiling_index_;
-      continue;
-    }
-    break;
-  }
-  if (tiling_index_ >= tilings_->size())
-    return;
-  if (!GetFirstTileAndCheckIfValid(&iterator_)) {
-    ++(*this);
-    return;
-  }
-  if (!TileMatchesRequiredFlags(tile_)) {
-    ++(*this);
-    return;
-  }
-}
-
-TilingSetEvictionQueue::PendingVisibleTilingIterator&
-    TilingSetEvictionQueue::PendingVisibleTilingIterator::
-    operator++() {
-  bool found_tile = AdvanceToNextTile(&iterator_);
-  while (found_tile && !TileMatchesRequiredFlags(tile_))
-    found_tile = AdvanceToNextTile(&iterator_);
-
-  while (!found_tile && (tiling_index_ + 1) < tilings_->size()) {
-    ++tiling_index_;
-    iterator_ = TilingData::DifferenceIterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->pending_visible_rect(),
-        (*tilings_)[tiling_index_]->current_visible_rect());
-    if (!iterator_)
-      continue;
-    found_tile = GetFirstTileAndCheckIfValid(&iterator_);
-    if (!found_tile)
-      found_tile = AdvanceToNextTile(&iterator_);
-    while (found_tile && !TileMatchesRequiredFlags(tile_))
-      found_tile = AdvanceToNextTile(&iterator_);
-  }
-  return *this;
-}
-
-bool TilingSetEvictionQueue::PendingVisibleTilingIterator::
-    TileMatchesRequiredFlags(const Tile* tile) const {
-  bool activation_flag_matches =
-      tile->required_for_activation() == return_required_for_activation_tiles_;
-  return activation_flag_matches;
 }
 
 // VisibleTilingIterator
@@ -488,22 +401,19 @@
     bool skip_shared_out_of_order_tiles,
     bool return_occluded_tiles,
     bool return_required_for_activation_tiles)
-    : EvictionRectIterator(tilings,
-                           tree,
-                           skip_shared_out_of_order_tiles,
-                           false /* skip_pending_visible_rect */),
+    : EvictionRectIterator(tilings, tree, skip_shared_out_of_order_tiles),
       return_occluded_tiles_(return_occluded_tiles),
       return_required_for_activation_tiles_(
           return_required_for_activation_tiles) {
   // Find the first tiling with a tile.
   while (tiling_index_ < tilings_->size()) {
-    if (!(*tilings_)[tiling_index_]->has_visible_rect_tiles()) {
+    if (!((*tilings_))[tiling_index_]->has_visible_rect_tiles()) {
       ++tiling_index_;
       continue;
     }
     iterator_ = TilingData::Iterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_visible_rect(), false);
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_visible_rect(), false);
     if (!iterator_) {
       ++tiling_index_;
       continue;
@@ -531,11 +441,11 @@
 
   while (!found_tile && (tiling_index_ + 1) < tilings_->size()) {
     ++tiling_index_;
-    if (!(*tilings_)[tiling_index_]->has_visible_rect_tiles())
+    if (!((*tilings_))[tiling_index_]->has_visible_rect_tiles())
       continue;
     iterator_ = TilingData::Iterator(
-        (*tilings_)[tiling_index_]->tiling_data(),
-        (*tilings_)[tiling_index_]->current_visible_rect(), false);
+        ((*tilings_))[tiling_index_]->tiling_data(),
+        ((*tilings_))[tiling_index_]->current_visible_rect(), false);
     if (!iterator_)
       continue;
     found_tile = GetFirstTileAndCheckIfValid(&iterator_);
@@ -551,7 +461,8 @@
     const Tile* tile) const {
   bool activation_flag_matches =
       tile->required_for_activation() == return_required_for_activation_tiles_;
-  bool occluded_flag_matches = tile->is_occluded() == return_occluded_tiles_;
+  bool occluded_flag_matches =
+      tile->is_occluded(tree_) == return_occluded_tiles_;
   return activation_flag_matches && occluded_flag_matches;
 }