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

cc/layers/picture_layer_unittest.cc

 // Copyright 2013 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.h"
 
 #include "base/thread_task_runner_handle.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/picture_layer_impl.h"
 #include "cc/test/fake_layer_tree_host.h"
@@ skipping 107 matching lines @@
 }
 
 // PicturePile uses the source frame number as a unit for measuring invalidation
 // frequency. When a pile moves between compositors, the frame number increases
 // non-monotonically. This executes that code path under this scenario allowing
 // for the code to verify correctness with DCHECKs.
 TEST(PictureLayerTest, NonMonotonicSourceFrameNumber) {
   LayerTreeSettings settings;
   settings.single_thread_proxy_scheduler = false;
   settings.use_zero_copy = true;
-  settings.use_one_copy = false;
 
   FakeLayerTreeHostClient host_client1(FakeLayerTreeHostClient::DIRECT_3D);
   FakeLayerTreeHostClient host_client2(FakeLayerTreeHostClient::DIRECT_3D);
   TestSharedBitmapManager shared_bitmap_manager;
   TestTaskGraphRunner task_graph_runner;
 
   MockContentLayerClient client;
   scoped_refptr<FakePictureLayer> layer =
       FakePictureLayer::Create(LayerSettings(), &client);
 
@@ skipping 34 matching lines @@
   // Do a main frame, record the picture layers. The frame number has changed
   // non-monotonically.
   layer->SetNeedsDisplay();
   host2->Composite(base::TimeTicks::Now());
   EXPECT_EQ(3, layer->update_count());
   EXPECT_EQ(1, host2->source_frame_number());
 }
 
 }  // namespace
 }  // namespace cc