Fix blurry content after disabling dev tools emulation

cc/layers/picture_layer_impl.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/layers/picture_layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 641 matching lines @@
     AddDamageRect(layer_damage_rect);
   }
   if (tile->draw_info().NeedsRaster()) {
     PictureLayerTiling* tiling =
         tilings_->FindTilingWithScale(tile->contents_scale());
     if (tiling)
       tiling->set_all_tiles_done(false);
   }
 }
 
+void PictureLayerImpl::ForceRecalculateRasterScales() {
+  ResetRasterScale();
+}
+
 void PictureLayerImpl::DidBeginTracing() {
   raster_source_->DidBeginTracing();
 }
 
 void PictureLayerImpl::ReleaseResources() {
   // Recreate tilings with new settings, since some of those might change when
   // we release resources.
   tilings_ = nullptr;
   ResetRasterScale();
 }
@@ skipping 663 matching lines @@
 bool PictureLayerImpl::IsOnActiveOrPendingTree() const {
   return !layer_tree_impl()->IsRecycleTree();
 }
 
 bool PictureLayerImpl::HasValidTilePriorities() const {
   return IsOnActiveOrPendingTree() &&
          is_drawn_render_surface_layer_list_member();
 }
 
 }  // namespace cc