services/ui: Remove deprecated gpu code

services/ui/common/gpu_service.h

Index: services/ui/common/gpu_service.h
diff --git a/services/ui/common/gpu_service.h b/services/ui/common/gpu_service.h
index 7a680771736061acad4673cc7cee40b6b3324ee9..7308754eac55f45c1c5ac0d7b234f8e75e16e9cd 100644
--- a/services/ui/common/gpu_service.h
+++ b/services/ui/common/gpu_service.h
@@ -34,8 +34,6 @@ class MUS_COMMON_EXPORT GpuService : public gpu::GpuChannelHostFactory {
     return gpu_memory_buffer_manager_.get();
   }
 
-  static bool UseChromeGpuCommandBuffer();
-
   // The GpuService has to be initialized in the main thread before establishing
   // the gpu channel.
   static void Initialize(shell::Connector* connector);