Revert "cc: Remove layers that are not drawn from tile manager."

cc/resources/tile_manager.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/tile_manager.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 
@@ skipping 660 matching lines @@
         !mts.tile_versions[mts.raster_mode].raster_task_) {
       FreeResourcesForTile(tile);
       continue;
     }
 
     // Insert the tile into a priority set.
     tiles->InsertTile(tile, mts.bin);
   }
 }
 
-void TileManager::CleanUpLayers() {
-  for (size_t i = 0; i < layers_.size(); ++i) {
-    if (layers_[i]->IsDrawnRenderSurfaceLayerListMember())
-      continue;
-
-    layers_[i]->DidUnregisterLayer();
-    std::swap(layers_[i], layers_.back());
-    layers_.pop_back();
-    --i;
-    prioritized_tiles_dirty_ = true;
-  }
-}
-
 void TileManager::ManageTiles(const GlobalStateThatImpactsTilePriority& state) {
   TRACE_EVENT0("cc", "TileManager::ManageTiles");
 
   // Update internal state.
   if (state != global_state_) {
     global_state_ = state;
     prioritized_tiles_dirty_ = true;
   }
 
-  CleanUpLayers();
-
   // We need to call CheckForCompletedTasks() once in-between each call
   // to ScheduleTasks() to prevent canceled tasks from being scheduled.
   if (!did_check_for_completed_tasks_since_last_schedule_tasks_) {
     rasterizer_delegate_->CheckForCompletedTasks();
     did_check_for_completed_tasks_since_last_schedule_tasks_ = true;
   }
 
   UpdatePrioritizedTileSetIfNeeded();
 
   TileVector tiles_that_need_to_be_rasterized;
@@ skipping 910 matching lines @@
 
   if (b_priority.resolution != a_priority.resolution) {
     return (prioritize_low_res && b_priority.resolution == LOW_RESOLUTION) ||
            (!prioritize_low_res && b_priority.resolution == HIGH_RESOLUTION) ||
            (a_priority.resolution == NON_IDEAL_RESOLUTION);
   }
   return a_priority.IsHigherPriorityThan(b_priority);
 }
 
 }  // namespace cc