cc: one copy is default as well as final fallback.

components/html_viewer/web_layer_tree_view_impl.cc

 // Copyright 2014 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 "components/html_viewer/web_layer_tree_view_impl.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "cc/blink/web_layer_impl.h"
 #include "cc/layers/layer.h"
 #include "cc/output/begin_frame_args.h"
@@ skipping 19 matching lines @@
       weak_factory_(this) {
   main_thread_bound_weak_ptr_ = weak_factory_.GetWeakPtr();
 
   cc::LayerTreeSettings settings;
 
   // Must match the value of
   // blink::RuntimeEnabledFeature::slimmingPaintEnabled()
   settings.use_display_lists = true;
 
   settings.use_image_texture_target = GL_TEXTURE_2D;
-  settings.use_one_copy = true;
   // TODO(jam): use multiple compositor raster threads and set gather_pixel_refs
   // accordingly (see content).
 
   // For web contents, layer transforms should scale up the contents of layers
   // to keep content always crisp when possible.
   settings.layer_transforms_should_scale_layer_contents = true;
 
   cc::SharedBitmapManager* shared_bitmap_manager = nullptr;
 
   cc::LayerTreeHost::InitParams params;
@@ skipping 192 matching lines @@
       base::Bind(&WebLayerTreeViewImpl::DidCreateSurfaceOnMainThread,
                  main_thread_bound_weak_ptr_,
                  id));
 }
 
 void WebLayerTreeViewImpl::DidCreateSurfaceOnMainThread(cc::SurfaceId id) {
   view_->SetSurfaceId(mojo::SurfaceId::From(id));
 }
 
 }  // namespace html_viewer