Move frame_sink_id management to framesink_manager.cc/h from

services/ui/surfaces/display_compositor.h

Index: services/ui/surfaces/display_compositor.h
diff --git a/services/ui/surfaces/display_compositor.h b/services/ui/surfaces/display_compositor.h
index 24f7338e92cfa2afab32d26baac1ba7b2ee6485f..e375746a9a1cb2ba6e42a2de9a19eaf266ef5320 100644
--- a/services/ui/surfaces/display_compositor.h
+++ b/services/ui/surfaces/display_compositor.h
@@ -15,6 +15,7 @@
 #include "base/threading/thread_checker.h"
 #include "cc/ipc/display_compositor.mojom.h"
 #include "cc/surfaces/frame_sink_id.h"
+#include "cc/surfaces/framesink_manager.h"
 #include "cc/surfaces/local_surface_id.h"
 #include "cc/surfaces/surface_id.h"
 #include "cc/surfaces/surface_manager.h"
@@ -108,6 +109,7 @@ class DisplayCompositor
   // destroyed in order to ensure that all other objects that depend on it have
   // access to a valid pointer for the entirety of their liftimes.
   cc::SurfaceManager manager_;
+  cc::FrameSinkManager framesink_manager_;
 
   scoped_refptr<gpu::InProcessCommandBuffer::Service> gpu_service_;
   std::unique_ptr<gpu::GpuMemoryBufferManager> gpu_memory_buffer_manager_;