Move DisplayCompositor code to new component.

services/ui/gpu/gpu_main.cc

Index: services/ui/gpu/gpu_main.cc
diff --git a/services/ui/gpu/gpu_main.cc b/services/ui/gpu/gpu_main.cc
index 8a7893ef197d225c52239dc24d984805b53f2bea..9d5102487d7c483f16248a875c91482240fdd919 100644
--- a/services/ui/gpu/gpu_main.cc
+++ b/services/ui/gpu/gpu_main.cc
@@ -211,9 +211,10 @@ void GpuMain::CreateDisplayCompositorOnCompositorThread(
 
   gpu_internal_.Bind(std::move(gpu_service_info));
 
-  display_compositor_ = base::MakeUnique<DisplayCompositor>(
-      gpu_command_service_, base::MakeUnique<ServerGpuMemoryBufferManager>(
-                                gpu_internal_.get(), 1 /* client_id */),
+  display_compositor_ = base::MakeUnique<frame_sinks::DisplayCompositor>(
+      gpu_command_service_,
+      base::MakeUnique<ServerGpuMemoryBufferManager>(gpu_internal_.get(),
+                                                     1 /* client_id */),
       image_factory, std::move(request), std::move(client));
 }