cc: Separate the priority from the tile and put in new PrioritizedTile

cc/resources/eviction_tile_priority_queue.cc

 // Copyright 2014 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/eviction_tile_priority_queue.h"
 
 namespace cc {
 
 namespace {
 
 class EvictionOrderComparator {
  public:
   explicit EvictionOrderComparator(TreePriority tree_priority)
       : tree_priority_(tree_priority) {}
 
   bool operator()(const TilingSetEvictionQueue* a_queue,
                   const TilingSetEvictionQueue* b_queue) const {
     // Note that in this function, we have to return true if and only if
     // b is strictly lower priority than a.
-    const Tile* a_tile = a_queue->Top();
-    const Tile* b_tile = b_queue->Top();
+    const PrioritizedTile& a_tile = a_queue->Top();
+    const PrioritizedTile& b_tile = b_queue->Top();
 
-    const TilePriority& a_priority = a_tile->priority();
-    const TilePriority& b_priority = b_tile->priority();
+    const TilePriority& a_priority = a_tile.priority();
+    const TilePriority& b_priority = b_tile.priority();
     bool prioritize_low_res = tree_priority_ == SMOOTHNESS_TAKES_PRIORITY;
 
     // If the priority bin differs, b is lower priority if it has the higher
     // priority bin.
     if (a_priority.priority_bin != b_priority.priority_bin)
       return b_priority.priority_bin > a_priority.priority_bin;
 
     // Otherwise if the resolution differs, then the order will be determined by
     // whether we prioritize low res or not.
     // TODO(vmpstr): Remove this when TilePriority is no longer a member of Tile
     // class but instead produced by the iterators.
     if (b_priority.resolution != a_priority.resolution) {
       // Non ideal resolution should be sorted higher than other resolutions.
       if (a_priority.resolution == NON_IDEAL_RESOLUTION)
         return false;
 
       if (b_priority.resolution == NON_IDEAL_RESOLUTION)
         return true;
 
       if (prioritize_low_res)
         return a_priority.resolution == LOW_RESOLUTION;
       return a_priority.resolution == HIGH_RESOLUTION;
     }
 
     // Otherwise if the occlusion differs, b is lower priority if it is
     // occluded.
-    bool a_is_occluded = a_tile->is_occluded();
-    bool b_is_occluded = b_tile->is_occluded();
+    bool a_is_occluded = a_tile.is_occluded();
+    bool b_is_occluded = b_tile.is_occluded();
     if (a_is_occluded != b_is_occluded)
       return b_is_occluded;
 
     // b is lower priorty if it is farther from visible.
     return b_priority.distance_to_visible > a_priority.distance_to_visible;
   }
 
  private:
   TreePriority tree_priority_;
 };
@@ skipping 30 matching lines @@
 
   CreateTilingSetEvictionQueues(active_layers, tree_priority, &active_queues_);
   CreateTilingSetEvictionQueues(pending_layers, tree_priority,
                                 &pending_queues_);
 }
 
 bool EvictionTilePriorityQueue::IsEmpty() const {
   return active_queues_.empty() && pending_queues_.empty();
 }
 
-Tile* EvictionTilePriorityQueue::Top() {
+const PrioritizedTile& EvictionTilePriorityQueue::Top() const {
   DCHECK(!IsEmpty());
-  ScopedPtrVector<TilingSetEvictionQueue>& next_queues = GetNextQueues();
+  const ScopedPtrVector<TilingSetEvictionQueue>& next_queues = GetNextQueues();
   return next_queues.front()->Top();
 }
 
 void EvictionTilePriorityQueue::Pop() {
   DCHECK(!IsEmpty());
 
   ScopedPtrVector<TilingSetEvictionQueue>& next_queues = GetNextQueues();
   next_queues.pop_heap(EvictionOrderComparator(tree_priority_));
   TilingSetEvictionQueue* queue = next_queues.back();
   queue->Pop();
 
   // Remove empty queues.
   if (queue->IsEmpty())
     next_queues.pop_back();
   else
     next_queues.push_heap(EvictionOrderComparator(tree_priority_));
 }
 
 ScopedPtrVector<TilingSetEvictionQueue>&
 EvictionTilePriorityQueue::GetNextQueues() {
+  return const_cast<ScopedPtrVector<TilingSetEvictionQueue>&>(
+      static_cast<const EvictionTilePriorityQueue*>(this)->GetNextQueues());
+}
+
+const ScopedPtrVector<TilingSetEvictionQueue>&
+EvictionTilePriorityQueue::GetNextQueues() const {
   DCHECK(!IsEmpty());
 
   // If we only have one queue with tiles, return it.
   if (active_queues_.empty())
     return pending_queues_;
   if (pending_queues_.empty())
     return active_queues_;
 
-  const Tile* active_tile = active_queues_.front()->Top();
-  const Tile* pending_tile = pending_queues_.front()->Top();
+  const PrioritizedTile& active_tile = active_queues_.front()->Top();
+  const PrioritizedTile& pending_tile = pending_queues_.front()->Top();
 
-  const TilePriority& active_priority = active_tile->priority();
-  const TilePriority& pending_priority = pending_tile->priority();
+  const TilePriority& active_priority = active_tile.priority();
+  const TilePriority& pending_priority = pending_tile.priority();
 
   // If the bins are the same and activation differs, then return the tree of
   // the tile not required for activation.
   if (active_priority.priority_bin == pending_priority.priority_bin &&
-      active_tile->required_for_activation() !=
-          pending_tile->required_for_activation()) {
-    return active_tile->required_for_activation() ? pending_queues_
-                                                  : active_queues_;
+      active_tile.tile()->required_for_activation() !=
+          pending_tile.tile()->required_for_activation()) {
+    return active_tile.tile()->required_for_activation() ? pending_queues_
+                                                         : active_queues_;
   }
 
   // Return tile with a lower priority.
   if (pending_priority.IsHigherPriorityThan(active_priority))
     return active_queues_;
   return pending_queues_;
 }
 
 }  // namespace cc