cc: Fix const value pattern by replacing it by non-const or reference.

cc/tiles/prioritized_tile.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/prioritized_tile.h"
 
 #include "cc/debug/traced_value.h"
 #include "cc/tiles/picture_layer_tiling.h"
 
 namespace cc {
 
 PrioritizedTile::PrioritizedTile() = default;
 
 PrioritizedTile::PrioritizedTile(Tile* tile,
                                  const PictureLayerTiling* source_tiling,
-                                 const TilePriority priority,
+                                 const TilePriority& priority,
                                  bool is_occluded,
                                  bool is_process_for_images_only)
     : tile_(tile),
       source_tiling_(source_tiling),
       priority_(priority),
       is_occluded_(is_occluded),
       is_process_for_images_only_(is_process_for_images_only) {}
 
 PrioritizedTile::~PrioritizedTile() = default;
 
 void PrioritizedTile::AsValueInto(base::trace_event::TracedValue* value) const {
   tile_->AsValueInto(value);
 
   TracedValue::SetIDRef(raster_source().get(), value, "picture_pile");
 
   value->BeginDictionary("combined_priority");
   priority().AsValueInto(value);
   value->SetBoolean("is_occluded", is_occluded_);
   value->EndDictionary();
 
   value->SetString("resolution", TileResolutionToString(priority().resolution));
 }
 
 }  // namespace cc