cc: Move LayerImpl::AddChild and RemoveChild to LayerImplTestProperties

cc/layers/video_layer_impl_unittest.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 "cc/layers/video_layer_impl.h"
 
 #include <stddef.h>
 
 #include "cc/layers/video_frame_provider_client_impl.h"
 #include "cc/output/context_provider.h"
@@ skipping 89 matching lines @@
   layer_impl->SetDrawsContent(true);
   const auto& draw_properties = layer_impl->draw_properties();
 
   FakeVideoFrameProvider provider;
   std::unique_ptr<VideoLayerImpl> video_layer_impl = VideoLayerImpl::Create(
       active_tree, 4, &provider, media::VIDEO_ROTATION_0);
   video_layer_impl->SetBounds(layer_size);
   video_layer_impl->SetDrawsContent(true);
   video_layer_impl->SetContentsOpaque(true);
 
-  layer_impl->AddChild(std::move(video_layer_impl));
+  layer_impl->test_properties()->AddChild(std::move(video_layer_impl));
   active_tree->SetRootLayer(std::move(layer_impl));
 
   active_tree->BuildLayerListAndPropertyTreesForTesting();
 
   active_tree->UpdateDrawProperties(false);
 
   // We don't have a frame yet, so the video doesn't occlude the layer below it.
   EXPECT_FALSE(draw_properties.occlusion_in_content_space.IsOccluded(visible));
 
   scoped_refptr<media::VideoFrame> video_frame = media::VideoFrame::CreateFrame(
@@ skipping 247 matching lines @@
   const YUVVideoDrawQuad* yuv_draw_quad =
       static_cast<const YUVVideoDrawQuad*>(draw_quad);
   EXPECT_EQ(yuv_draw_quad->uv_tex_size.height(),
             (yuv_draw_quad->ya_tex_size.height() + 1) / 2);
   EXPECT_EQ(yuv_draw_quad->uv_tex_size.width(),
             (yuv_draw_quad->ya_tex_size.width() + 1) / 2);
 }
 
 }  // namespace
 }  // namespace cc