cc: Properly detect tiles that are needed now.

cc/tiles/raster_tile_priority_queue_all.cc

 // Copyright 2015 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/tiles/raster_tile_priority_queue_all.h"
 
 #include "base/memory/ptr_util.h"
 #include "cc/tiles/tiling_set_raster_queue_all.h"
 
 namespace cc {
@@ skipping 127 matching lines @@
     return active_queues_;
 
   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();
 
   switch (tree_priority_) {
     case SMOOTHNESS_TAKES_PRIORITY: {
-      // If we're down to eventually bin tiles on the active tree and there
-      // is a pending tree, process the entire pending tree to allow tiles
-      // required for activation to be initialized when memory policy only
-      // allows prepaint. The eventually bin tiles on the active tree are
-      // lowest priority since that work is likely to be thrown away when
-      // we activate.
-      if (active_priority.priority_bin == TilePriority::EVENTUALLY)
+      // If we're done with required tiles on the active tree, then process
+      // required tiles on the pending tree. If either the active tree has
+      // required tiles, or none of the trees have required tiles, then process
+      // the active tree by default.
+      bool active_tree_has_required_tiles =
+          active_tile.tile()->required_for_activation() ||
+          active_tile.tile()->required_for_draw();
+      bool pending_tree_has_required_tiles =
+          pending_tile.tile()->required_for_activation();
+      if (!active_tree_has_required_tiles && pending_tree_has_required_tiles)
         return pending_queues_;
       return active_queues_;
     }
     case NEW_CONTENT_TAKES_PRIORITY: {
       // If we're down to soon bin tiles on the pending tree, process the
       // active tree to allow tiles required for activation to be initialized
       // when memory policy only allows prepaint. Note that active required for
       // activation tiles might come from either now or soon bins.
       if (pending_priority.priority_bin >= TilePriority::SOON &&
           active_priority.priority_bin <= TilePriority::SOON) {
         return active_queues_;
       }
       return pending_queues_;
     }
     case SAME_PRIORITY_FOR_BOTH_TREES: {
       if (active_priority.IsHigherPriorityThan(pending_priority))
         return active_queues_;
       return pending_queues_;
     }
     default:
       NOTREACHED();
       return active_queues_;
   }
 }
 
 }  // namespace cc