cc: Remove unused should_update_tile_priorities.

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index 3dbce3cb6dab0bb1327dfb34bb0811fbccc7b8b6..d86ef8ccf9e83b4361e640464e2ea1b6b60b376c 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -82,7 +82,6 @@ PictureLayerImpl::PictureLayerImpl(LayerTreeImpl* tree_impl,
       low_res_raster_contents_scale_(0.f),
       raster_source_scale_is_fixed_(false),
       was_screen_space_transform_animating_(false),
-      should_update_tile_priorities_(false),
       only_used_low_res_last_append_quads_(false),
       is_mask_(is_mask),
       nearest_neighbor_(false) {
@@ -462,8 +461,6 @@ bool PictureLayerImpl::UpdateTiles(const Occlusion& occlusion_in_content_space,
   if (draw_transform_is_animating())
     raster_source_->SetShouldAttemptToUseDistanceFieldText();
 
-  should_update_tile_priorities_ = true;
-
   return UpdateTilePriorities(occlusion_in_content_space);
 }
 
@@ -1076,10 +1073,6 @@ void PictureLayerImpl::ResetRasterScale() {
   raster_contents_scale_ = 0.f;
   low_res_raster_contents_scale_ = 0.f;
   raster_source_scale_is_fixed_ = false;
-
-  // When raster scales aren't valid, don't update tile priorities until
-  // this layer has been updated via UpdateDrawProperties.
-  should_update_tile_priorities_ = false;
 }
 
 bool PictureLayerImpl::CanHaveTilings() const {